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Rated 5 out of 5 by from Amazing warmth & comfort I bought this Therm-a-Rest MondoKing 3D mattress after trying a smaller other type that didn't quite fit my needs car camping mainly because of the width. I just returned from a 3 night camping trip at Yosemite, camping at 8,600 ft and low 30 F weather at night. I was so amazingly comfortable and warm all three night that I can't wait to go camping again. My camp neighbors had to pack up after the first night because they were freezing on their basic blow up mattress. Not once did I feel any coolness from the bottom and I actually slept better than in my bed at home - meaning without back pain (most likely because it's nice and firm). Absolutely worth the money!!!
Date published: 2016-09-14
Rated 5 out of 5 by from Better than a real mattress This thing is huge but perfect for my 6'6" husband. He has a bad back but we were finally able to go camping using this combined with a cot. Our first night camping, I slept on my self-inflating mattress pad on the floor. Mid-day, I took a nap in this Thermarest and it was ridiculously comfortable. I question that it's more comfortable than our memory foam mattress at home. It's pricey but worth every penny for anyone with back issues. We can finally go camping. Thank you Thermarest!
Date published: 2017-06-20
Rated 5 out of 5 by from best mat ever Bought this after going through the both the rei camp bed 3.5 and mountain summit gear 3.5,. I returned both of those mats because they started leaking. I also went through 2 other 4 inch pads I bought off ebay. they all started leaking within a year or two. I decide to pay more for the thermarest name and am glad i did. The foam is softer and more comfortable than any of my previous car camping mats. I have thermarest mats i bought 20 years ago that never failed so I have great faith in the brand. I do take care of my mats all my previous leaks have been at the valves and delamintated seams not punctures from poor placement. Thermarest is made right here in the USA and backed by a solid warranty. I am confident this is the last mat I am going to buy. It did take 4 days to inflate fully the first time but who know how long it was packed up for. Now it inflates much faster , just don't buy it the day before your trip and you should be fine
Date published: 2016-06-04
Rated 5 out of 5 by from Maximum comfort with highest R-value I have over a dozen air beds, mattresses, and pads. This is my favorite portable total bed when I don't have to carry one a long way on my back. For insulation R-value it is much better than anything else available in winter, nothing else is close. For comfort, it is outstanding. Pricey but worth it.
Date published: 2016-05-27
Rated 5 out of 5 by from Exceptional overlanding mattress Works best as a car camping/overlanding mattress. After purchasing the Mondo King XXL, I removed it from its bag, allowed it to self-inflate, and stored it that way for a week before it's first use. Self-inflation is now rapid and complete - I felt no need to add additional air. It is a very warm and comfortable mattress, and before I packed it up after its first use, I opened the valves while laying on it to simulate a puncture. I felt like it was still very comfortable that way and am not concerned about a puncture ruining my nights sleep. If it does ever get a puncture, I might not even bother trying to fix it until the trip was over. The only difficult part is deflating it and rolling it up. It basically requires grasping with both hands and resting both of your knees on the rolled up portion and slowly roll it up towards the open valves. I attribute that difficulty to its strong self-inflation characteristic, and it really wasn't that big of a deal, it's just slower/more difficult to roll up than a regular air mattress. I'm very satisfied with my purchase.
Date published: 2016-10-16
Rated 5 out of 5 by from Just Like Home I was hesitant to get a 'comfort' thermarest. To date, I have owned the bare minimum and kept that as light weight gear. I skeptically ordered the MondoKing 3D before going on a multi week car camping trip to mountain bike. This is the most comfortable mattress ever. I am a princess with the pea. I need a firm mattress or else will have back pain upon waking and not sleep well. I literally slept as well with the MondoKing 3D as I do at home. (for those who don't care for a firm mattress, you have control of how much air you put in and how firm it is) The vertical sidewall, combined with the integrated sheet and quilt (sold separately) are absolute heaven. It is better than sleeping in your bed at home!
Date published: 2017-04-28
Rated 5 out of 5 by from Really good, very comfy Bought this several weeks ago at the Seattle flagship store and very happy with it. I bought the 25" wide one partially because the 30" one would probably be too large for my uses. Bulky, but very comfy.
Date published: 2016-04-06
Rated 5 out of 5 by from Wall to Wall Comfort We purchased two of these in September, and used them for the 3rd time this weekend. They’ve been on a family room floor once, and side by side in an REI Half Dome 2 Plus two times (where they fit perfectly, by the way). Best mattress pad I’ve owned. No issues with bottoming out (I’m 215#), and big enough to roll over on. It was like tackling a greased pig to get them back in the cinch sacks the first couple of times, but we developed a solid technique for deflating them so it has gotten easier. If they hold up, it will certainly be worth the investment.
Date published: 2017-11-19
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Questions & Answers

How does this compare to the Thermarest Dreamtime? What are comfort differences?

Asked by: triestep
The MondoKing 3D Camp Mattress is thicker by a half inch. The Dreamtime has a memory foam topper and micro fiber cover. While the Dreamtime is a tried and true classic, the MondoKing 3D is the largest mattress offered from this brand.
Answered by: REIservice
Date published: 2017-12-18

G'day. I'm currently trying to decide between two mats: the Thermarest Mondoking 3D XXL and the Exped Megamat 10 LXW. My issue is: I don't have either mat available nearby to test out for myself. So - in your opinion - which mat is the more comfortable?

Asked by: Andrew
I have had the Thermarest mondo King, Megamat XXL and Megamat duo by exped. I owned many (7) thermarest camp rests In the past 2.5 inches thick, and have one smaller thermarest for lightweight camping. Here's my take. I used the Megamat duo for car camping in a Tesla Model X 5 seater. The mat is a bit too wide and almost too long, the mondo King is also way too long as you can barely close the trunk unless it is slightly angled. The mega mat 10 is nearly ideal. The mondo King is almost impossible to deflate . It is not " cored foam" like the Exped and so it is not only heavier but the foam also resists compression so much that the last 2 feet of mattress is so hard to deflate while the rest wants to reinflate. I'm 187 lbs and couldn't do it. A 210 lb REI employee could not deflate it either when I returned it. I like the Exped Megamat 10 XXL because it is super easy to inflate and deflate, easy to fold and ultimately more comparable a surface for sleeping, the valves don't stick out ( so they don't get stepped on and cracked) and the inflator puff is a easy to use.  The Megamat duo is harder to deflate , considerably more so. But the space is wonderful. it's almost a full size bed. Now,,,,,, if you want to go wild, you take a Megamat duo and a Megamat 10 XXL and you can create a 77.25 X 82" mat , the same size as A KING SIZE BED, to which I add (2)  3" foam mattress toppers that can cover a king sized bed, making t  ,, simply the most comfortable wilderness sleep ever....that's luxury. So if you have to inflate and deflate this more than say 2 times a week, do not get the mondo King. If you have to deflate it more twhen 4 times a week you might not want the Megamat duo , and if you deflate 5 or more times a week you gotta get eh Exped mega Matt 10 XXL  which at 30" is pretty wide. The best use of the mondo King was as a pool float , just narrow enough so a girl is almost on top of you if you share it. The valves SUCK ON THE MONDO KING they are slow to fill and drain.  Now, if you do crack one, it is probably easier to fix than w bad Valve on a Megamat.
Answered by: Johnny Camper at 70 below
Date published: 2018-02-14

If I bought two of these in the XL size, it adds up to queen size dimensions. Would it make a decent queen sized bed for two adults and a toddler? I like to car camp using real bed sheets.

Asked by: FamilyCamper
my wife and I just used 2 XL set ups with a fitted sheet to snug them together, My 9 month old slept between us (soundly) all night. Noticed a little gap in the morning, but nothing that caused a disturbance. I am 6'2 200 and she is 5'6. We slept 3 nights on this set up pretty well.
Answered by: jthomasjohnson
Date published: 2017-10-28

I have an exped mat about the same size, but it is very noisy. It keeps my wife awake when I shift around on it. Is this one quieter? I need a quiet mat. Thanks!

Asked by: Scott Newsom
The surface material on this pad is likely softer and thus, quieter.
Answered by: REIservice
Date published: 2018-01-09

With the high insulation values of this mat, will it become uncomfortably warm on a hot summer night?

Asked by: Tief
A sleeping pad with a high insulation value will not be too warm for summer use.
Answered by: REIservice
Date published: 2017-08-03

When it is deflated how thick is it unrolled? 

Asked by: C2000
We're sorry, that information is not available. When fully compressed and rolled up the dimensions are 31 (L) x 7 (D) inches.
Answered by: REIservice
Date published: 2017-10-02

I only have 24" width for the mattress to fit between the seats in my car, the rest of the area is fine. Since the mattress inflates to 25" wide, will scrunching it there in the one place cause a problem?

Asked by: Moondancer
The mattress would still work well if inflated properly between the seats with only 24 inches of space, as long as the seats to not have any hard edges or protrusions that might cause the mattress to wear incorrectly where they come into contact.
Answered by: REIservice
Date published: 2017-01-26

The width of my van is 47" at it's narrowest point can I use 2 L size next to each other?

Asked by: Monika
Two of the large pads side-by-side will have a width of 50 inches. These are too wide for the narrowest point of your van.
Answered by: REIservice
Date published: 2017-08-27
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