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Discussion Starter · #1 · (Edited)
For those of you that want a TON of hot air at a very reasonable price...I have the answer! I do not have a cab enclosure and I needed something a little more rubust, so I decided to try one of the heaters from Summit Racing. For $250ish I ended up with more than I had hoped for and was also pleasantly surprised at how easy it was to install.
Here's the heater... http://www.summitracing.com/parts/sum-991102-1/overview/
Here's the duct kit... http://www.summitracing.com/parts/mar-mfa130
Here are the "Y" connectors needed to tap into the radiator hose... Universal Parts, Inc. - Y-Fitting 1" Radiator Hose to 5/8" Heater Hose
You will also need 2 pieces of 2"x 1/8" strap (one 5 1/4" and one 6 1/2") plus 4ft of 5/8" heater hose, a hand full of various sized hose clamps, some wire and a 15 amp inline fuse.
Here's the kit...
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Mounted the heater under the drivers seat. No need to drill anything on the Viking, as there are plenty of holes right where you need them in the seat support. You will have to drill 7 holes total in the two flat bar pieces so you can mount the heater...
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Tapped into the 1" radiator hose supply side under the center seat and then the return line from the core was routed over to the radiator return line under the passenger seat... Automotive tire Motor vehicle Automotive design Automotive exterior Gas
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Used a 3" hole saw and then mounted the vents under the driver's and passenger's seats... Automotive tire Gas Motor vehicle Audio equipment Automotive wheel system
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Here's the switch I ended up with (not the one it comes with). I also added a water temp gauge for fun too...still waiting on the sending unit adapter though. Pay no attention to the outside air temp, I had a drop light hanging close to the sending unit....it was reading 120 something earlier :)
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You can see where I ran the ducting in the other photos. You will need to run the the passenger's duct under the airbox and you will see a hole in the skid plate. I added a small piece of that 3" white plastic drain pipe you can get at Home Depot. This will protect the duct from the sticks and stuff that might rip it there. FYI: the 3" duct fits perfectly over the pipe! Pipeline transport Automotive tire Motor vehicle Automotive exhaust Automotive exterior

Ran the wires and bled the system. IMPORTANT: While researching this, this biggest complaint and reason for lack of heat is because of air trapped in the system. It's not that difficult to bleed the air and JBS has put out a great video on how to do this...do it EXACTLY how this video shows and you will have bo problems... [video=youtube;g0lszje5waU]https://www.youtube.com/watch?v=g0lszje5waU[/video]

After all this, I fired her up and WOW! This thing BLOWS a TON of HOT air! The reason I put the vents under the seats is because, without an enclosure, I wanted to be able to throw a blanket over our laps and let it hang to the floor...which would trap the heat. This should keep enough heat in there to at least take the edge off. I have not taken it for a ride yet and I know that it's going to be like driving my truck with the heat on and windows down. But I can tell you this...you cannot hold your hands over the vents for very long because it gets WAY too hot! I was so impressed that I added another rectangular vent under the center seat (seen in photos). Now I'm thinking might order and additional duct kit and run a duct under the center tunnel so I can put some vents under the dash blowing directly on the us.
This heater puts out an amazing 260cfm / 28,000BTU's. Once installed, the only thing you see are the vents and the heater switch. You can do the whole thing for right at $250ish and again...it is not a difficult install. You will spend more time taking all the stuff off to get to the area needed than anything else. If you want even more heat, Summit has a larger version as well... http://www.summitracing.com/parts/sum-991106/overview/

In short...I HIGHLY reccommend this unit! And for those of you with cab enclosures...this will toast your marshmallows! This puts out almost twice as many BTU's as Viking specific heaters for about a $100 less and you see nothing but the vents and heater switch. You can expand and run ducts and vents to better suit your own needs but you do have to put your own kit together. I'll post some pointers and more detailed stuff later. Now I just have to wait for my custom water temp gauge and sending unit adapter and I can finish it up.

PS: See post #3 in this thread for tips, pointers and additional info.

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This is very well done MnT. Thanks for the awesome documentation. We all appreciate it even though nobody says so. This will probably be a summer project for me.
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Discussion Starter · #3 · (Edited)
Here are some tips and info that will make this install easier...and the heater more functional.

#1. I spoke will several Folks over on the Jeep and Cobra forums and there is one common pointer they had. If your heater core does not specify flow direction or an inlet side...always run the input line to the bottom fitting. The number one reason people have issues with these not getting hot enough is air in the system. By running the water flow bottom to top, it helps push any trapped air out of the top of the heater core.
#2. When you get your "Y" connectors make sure you look into the 5/8" side. These things are stupid expensive for what you get. They are really nothing more than a straight 1" tube with a small hole drilled in it...and then a 5/8" piece welded at an angle. You will need to run a 1/2" drill bit down the small side and this will open it up a bunch. I ran water through mine (before and after) and it made a huge difference. For those of you that already have heaters intalled, and you are still not happy with the heat output, you might want to check yours. Having said that, most of the other Viking specific heaters are only rated at 14,600BTU's...so you may be getting all the heat they have? This one is rated at 28,000BTU's and the larger one is 40,000BTU's!
#3. Take a little sand paper and clean up the edges of the "Y" connectors. Also, be prepared to struggle a bit getting these on. The OEM radiator hose is not quite 1" and you are going to find that this is a VERY tight fit!
#4. When intsalling the ducts, make sure you trim them to length. If you leave a bunch of extra tucked in there, there is so much pressure on high that the lines will expand and you'll find that they will move around to the point that they might rub on things under there.
#5. Common 1" heater hose should fit over the 5/8" hose. So it's a good idea to put some 1" hose over the smaller hose anywhere it migh rub. You can see where I did this...look for the green stripe 1" hose in one of the photos.
#6 FYI: The heater I used draws 9.6 amps on high...and the larger heater draws 11.6 amps.
#7. This heater will not fit behind the dash. However, I'm pretty sure you could run some duct under the center floor, and then mount other vents...even a defrost. Note: Again, I'm "pretty sure" there is room under the floor...but you might want to confirm this.
#8. I was so impressed when I was done that I decided to add another rectangled vent under the center seat (see photos) so everyone would have heat...here is the link Nostalgic AC - Rectangle Underdash Vent Long - Dash Vents - Duct Hose & Vents (you will need about 3' of 2.5" ducting for this also)
#9. When I originally ordered my heater, I was told that the smaller heater came with the same switch as the one shown with the larger heater. This is not true...it's smaller, with a round knob. There is nothing wrong with the smaller switch, but I just liked the looks of the larger one. Anyways...if you look close at my first photo you can see the switch that this heater comes with. After some pressing phone calls, I was sent the larger switch.
#10. I have been told that a heater shutoff valve is not needed because, without the fan on and air blowing through the core, the radiant heat is not an issue. It would be simple to add an inline shutoff valve if you wanted to though.

For those of you with enclosures, if they are half way sealed, I can't imagine that you will need to run this heater on high....I mean it REALLY puts out some serious heat!

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WOW, so much info. You have done an awesome job with this and made better instructions than anything in think if ever done. You have great ideas and are very knowedgable. Thank you.

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Discussion Starter · #8 ·
For my type of riding, the answer would be "no." Having said that, if my tires leave the ground, or my ankles get wet, I have made a serious error in judgment! LOL!! Anyways, I do run through the water, mud and snow quite a bit and this mount location will give you no issues as long as the water isn't deeper that the height of the heater itself.

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Thanks to Mass and Monkey for paving the way for these heater installs. I just finished mine with an install similar to Monkey's (under hood) and I added defrost using eyeball outlets.

Heater mounted beside glovebox showing routing of the hoses.

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I used the "y" connector to provide air to both main vents, one vent near the glove box and the other is at drivers station pointing toward the feet.

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Hose going across to drivers vent

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Drivers side vent and hose

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I built a manifold to distribute the defrost air to the eyeball outlets using 3" PVC and plastic threaded hose barbs

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Notice the offset of the hose barb on the left, this is so it will clear the other heater hose once its attached to the heater box.

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I used plastic weld to glue in the fittings and the top plug for the pipe

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Here is a test fit of the manifold, note how the offset allows the barbs to straddle the heater hose for the main vents. The 3" pvc manifold will slide snugly down over the outlet on the heater box if you file away the hose tabs, in this picture the pvc manifold is too tall and the front fender assembly will not slide all the way down, I had to shorten the height of the pvc manifold to the point that the hose barbs (inside the manifold) rest on the outlet of the heater box. It ended up being about 3.5 inches tall or so.

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Here is an eyeball outlet mounted in front of cupholder, I used 3 total, one if front of each set of cup holders, then one in the center.

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Here is an underside view of the eyeball outlet and its air supply hose.

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Here is the manifold glued to the heater box and with all hoses attached. I did have to trim the upper right side of the plastic on the electrical compartment to fit around the pvc manifold,

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View of hose routing from inside the vehicle

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In this pic you can see the center and right eyeball outlets.

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Now that project is finished on to another.

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The eyeball outlets are directional and can be shut off individually (they are what you have over your head for air in airplanes) and seem like they will work just fine.

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Hello Everyone.....

I have been studying everyone's pictures and instructions for more than a month, and after doing my own additional research, I decided to install the same Summit/Jegs heater in my 2016 Viking 6 seater. This is how I did it....

First, I studied Mass-n-trash's methods and thoughts. I, too, will not be using a fully enclosed cab since I live in south east Texas. For the few days of cool weather we get down here, an enclosed cab doesn't really make any sense unless you are going to add a cab air conditioner to the mix.....Which I have considered.....But have not yet tried. On a typical southern Texas winter day, it can be anywhere from 20F up to 80F. And if you are not familiar with Texas "winters", just know we have TON's of humidity, and a 50F morning can be quite bone chilling when out and about on the viking. That said, I really like the thought process from Mass-n-trash (MNT) about throwing a blanket over you and staying warm until it is no longer needed. So I choose to mount my vents under the driver and passenger seat as well. Both pointing forward and slightly up between the legs. I must say that MNT is right! This thing puts out TONS of hot air.....HOLY COW!!! It took me 2 weeks to do the install around other honey-do's and work, but I finally got it done. So i'll walk you through how I did it on the 6 seater, and hopefully I have all of the pictures to go with it. If not, i'll get them.


1 - I am not one of those people who will sink their viking in a mud hole. I bought it to ride and and have fun on with the family, not to destroy a $14,000 machine! If water manages to reach the middle of my tire, I am looking for a way out, or backing up. Any more than that, and I have made a huge judgement error....

2 - Picture Quality....The forum will only let me upload a picture that is 97.7kb or less in size. So I have to reduce the quality of the pics, and i'm hoping they will turn out ok. If you want a full resolution pic, I can send you one if you just ask. Hopefully these will be good enough for discussions sake.


My parts are pretty much that same as MNT's, except I took advantage of my AmazonPrime membership and ordered it all from there with free shipping. Pricing was about the same as Summit Racing and Jeggs, so it still cost about the same in the end. I did not think to lay my out all nice and pretty on the carpet though.... Thumbs up to MNT for doing that. In the end, we have the same parts, just FYI.

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Mounting location of the heater:

MNT choose to mount his heater under the drivers seat. I choose to mount mine under the middle passenger seat in the front. This way, I could keep the storage box under my drivers seat, and the heater just fit so well in the middle, it was hard to not put it there. Also there's a very deep, odd shaped storage box under the front middle seat that I never used, so taking it out was certainly an option.

This picture shows the seat removed, and the storage box removed in the middle.

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This picture shows the heater mounted in the middle.

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Notice the brackets that hold the heater up. Those are the original L brackets that came with the heater, but I had to modify them as shown here. The one on the left is the modified bracket. The one one the right, is the original shape that came with the heater from the factory.

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It just so happened that the mounting slots in the bracket are just barely wide enough for the original seat bolt to pass though them. So I choose to use those original seat bolts to mount the heater with. I set the seat back on top of the bracket, and put the bolts through the seat, and through the heater bracket and tightened them down at a later point. For now, they are just holding it in place.

As i'm figuring out how to do the duct work, it just so happens that the ducts will exit the heater box, and nicely turn down behind the floor panel and go under both the driver seat, and the front passenger seat without getting caught on anything. It is unbelievable how well this whole thing fits. Its almost like it was made for this 6 seater viking.

Oh and I did not have to fabricate anything! I only had to bend the mounting brackets for the heater, and I did that with a bench vise and some country boy muscle. :)

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I ran the heater duct to the driver side, again, without any obstructions.

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And, with the help of my jigsaw and some patience, I cut the hole for the vent to be mounted in under the driver seat. I did make sure that the vent was mounted low enough under the seat so that the original storage box under the drivers seat could be re-installed and reused without hitting the vent or duct work. I also left enough slack in the duct work so that when I buy another vent kit, I can Y it and put a vent under the rear of the drivers seat pointing to the back seat passengers. UPDATE>> After some more looking, I might end up splitting the duct and running it under the floor and bring it up under the rear passenger seats and mounting the vents in the same way I mounted the front ones. But I have not done that yet. While I had everything apart, I discovered that it might be possible. More on that later, if I ever do it. And I probably will. I just want to install a second battery under the drivers side rear passenger seat, so I need to do that first. If there is room, and I think there will be, then i'll put the vents back there.

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Here is a picture of the duct work with the floor panel removed. It had to come out so I could do the plumbing into the radiator lines.

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This is a picture looking under the heater from the front of the viking. Its hard to see the spacing, but there is about 1.5 to 2inches of space between that drive shaft mount and the bottom of the heater. You can also see the ducts not hitting anything either.

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Its a little hard to see, but here are the heater hoses (5/8's inch) that are connected to the heater unit and carefully curved down and into the bottom of the viking next to the original radiator lines. Note: If you didn't already know, the 6 seater viking has metal radiator lines that run from the back of the viking to the front to avoid running actual hose. I guess Yamaha figured this was easier to install or manage if necessary. That said, you will need 10ft of heater hose to be able to get two 5ft runs from the heater up to the splice point. If you look closely, you will also see the big black shiny pipe in the middle of the picture above the hoses. This is the middle seat frame mounted back into place as I mentioned above.

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I ran the two 5ft hoses towards the front of the vehicle in a strategic fashion. I do want to also point out, like someone else has, that the heater does not have an inlet or outlet on the heater core. However, the top hose of the heater should be tied into the return line that goes back to the engine, and the bottom should be tied into the hot line coming from the engine going to the radiator. This is so that all of the air in the heater core is, ideally, pushed out and back towards the engine. On the top of the engine, there is a coolant bleeder bolt that will allow you to bleed the air out of the coolant system. In my research, it is very important to bleed the coolant lines of air once you are done. More on that below...

The top line of the of the heater runs down the right side of the viking towards the front of the bike, and then makes a left hand turn at the front of the floor board, and ties into the return radiator line as shown here...

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The bottom line of the heater runs down and curves over, very comfortably I might add, under the drive shaft to the drivers side of the vehicle, and then curves over to the front passenger side where it ties into the hot line.

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Since I can't post more than 15 pictures per post, I'm going to start a second post now.....hold tight.....
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Picking up from the previous post.....

Here's a picture from further back....

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Now....About the T connectors that I searched high and low for.....

I, personally, do not like any of the plastic ones that you can buy for $30 or $35 over the counter. My thinking is that plastic gets brittle over time, and the last thing I wanted was a cheap plastic connector forcing me to be stranded in the hills when we go riding. Now I know that some of these plastic connectors can be pretty strong and meant to handle heat, but honestly, I'd rather a stronger, brass connector. So I did some digging for nearly a week, and finally had the idea to get some PEX tubing T connectors. So I ordered 2 of these (TEE-443) from pexsuperstore.com. It is a 1"x1"x3/4". And before you say, WAIT! Wasn't he using 5/8' heater hose......Yes I am. PEX is sized differently than most other hoses for some reason. In the end, I ordered about $30.00 bucks worth of T connectors of various sizes, and in the end, this is the one that fit.

I did not actually drain my whole coolant system, by the way. I used a clamp and clamped the radiator lines about 8-10 inches from the factory splice point to keep the radiator from draining out on to the floor. Then I used PCV cutters to cut the original radiator line straight, and I had my hose clamps and T connectors ready to be plugged in to minimize coolant loss. I expected to loose some coolant, but I did not want to go through the process of emptying the whole system. And it worked pretty well. I ended up loosing anywhere from 1/4 to 1/2 gallon of coolant if I had to guess. I let it fall on the concrete floor since I didn't have a drain pan worth using, and I just cleaned it up once I was done.

Of the 5ft heater hose runs, I need up cutting of about 2 inches off of one side, and about 4-5 inches off of the other one so that they would lay comfortably in the bottom of the floor under the original lines. I cut off as little as possible so I can have some slack in case I ever need it. but not enough to flop around and get in the way.

Once I made all of my connections, I topped off my radiator again, and cranked the viking to let it circulate the coolant. After 3-4 minutes of running, and no high temp lights, the heater started to get just a little warm. So I knew the water was circulating through it. But I needed to still bleed the coolant lines.

I do want to make one statement about bleeding the coolant. If you let the viking run a few minutes and the motor warms up like mine did, let it sit for 15-20minutes or more before you try to bleed that thing! I wasn't thinking, and that motor was very warm, not hot, and when I unscrewed the bleeder bolt, all of the hot air in the line shot out, and then suddenly, so did the hot coolant. This was one of my "DOH!" moments.... So I had to get the bolt put back in with hot coolant coming out. It was not pleasant. I used a 8mm wrench. In hindsight, and as I bled it again later, I used an 8mm 1/4 socket on a 6inch extension. This allowed it to spew a little coolant, and I didn't have to put the bolt back in by hand.

Lastly, here is the ambient air temperature in my garage/shop when I cranked up the viking for the last time to try out the heater.

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After letting it run for about 10 minutes, and me holding my foot on the gas slightly to hold a higher RPM, the fan still never kicked on, but I could tell when the thermostat opened up. The air temperature coming out of the vents shot up very quickly. And after about 2 minutes, it was so hot, I couldn't hold my hand over the vent. And it was still on low.

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I wanted to put the heater switch on the dash, but since it is not a water proof switch, I decided that its not a good idea to put it in the dash with the back side exposed to the front tires and all of their debris. So I mounted it between the drivers seat, and the middle seat on the front panel down low. This way I can adjust the speed of the blower without reaching between my legs, and so that my passenger in the front, usually an adult, can also reach over and get to it. It is low profile enough that it does not get in the way of anyones legs and is very easy to get too.

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Conclusion Notes:

1 - Prices are comparable to MNT's prices. Overall, I have about $250.00 tied up in the heater install.
2 - I bought a 10ft piece of 5/8inch heater hose at O'Reilly Auto Parts for about $1.50 a foot I think. Can't be sure though on the price...
3 - The heater is being held in place by sandwiching the brackets between the seat frame and the chassis frame. Because of that, the blower motor causes quite a bit of annoying vibration when running on high. So I will likely get longer bolts for the center seat bracket, and come up with some kind of bushings to put under and above the heater brackets to reduce vibration and noise.
4 - The heater will suck in air from anywhere it can get it, and there is no filter of any kind to protect the coil from getting dirty. I'm not a big fan of that, but I also do not go riding in very sandy areas. The fresh air is pulled from the cab area, and under the seats, and is not super dirty in my riding environments. But if you decide to go swimming while still driving your viking, it might be a problem for your heater.

I think that it! I hope it helps someone!
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Where did you connect your temperature sensor too that you installed in the dash? I'm looking for a place to connect mine too as well.

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Bringing this back to life for winter. You guys that have put these in, how was your summer time? Where I am going with this is with this coolant routing, some coolant is allowed to circulate totally bypassing the radiator. For winter time, I doubt there are any issues. However, in summer time, was/is there any overheating going on due to some coolant circulating via your heater circuit completely by passing the radiator? I put one of these in my Rhino years ago but it was ran completely in series out of the top of the engine. I was worried the 5/8 line would cause a bottleneck but it didn’t. No cooling issues. How’s your engine temps with this plumbing in summertime? Ever have to use your heater for secondary radiator functions?

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My summertime seemed good. I did not have any overheating issues on my buggy but to be honest, I’m not someone who pushes the machine to its max often. I would say mine spends most of its time with about 500-600lbs worth of people and dogs on board at any given time and runs about 20-30mph most days. When I went out trail riding back in August, I spent a lot of time in 4x4 Low and did not have any issues. My radiator fan cycled many times, but I never got the impression it was running hot or got the idiot light for high temp. Unfortunately, I have drug my feet on installing the temp sensor to run my gauge so I do not have a running number for you. Only that the factory radiator did not seem to cycle any more than usual for me. I know that’s not very helpful, but it’s all I got. :|

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