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MondoKing 3D

The biggest Therm-a-Rest mattress ever.

Are you always on the lookout for something bigger and better? Your ship has arrived with the MondoKing 3D. Simply put, the MondoKing 3D is the biggest Therm-a-Rest® mattress ever. Vertical sidewalls create 20% more usable sleep surface so you have room to sleep like starfish. Dual valves allow compressible foam core to expand and inflate quickly when unpacked. A new and improved stuff sack with easy-carry handle is also included.

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$179.95
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How to Care for Your Therm-a-Rest® Mattress

Are you always on the lookout for something bigger and better? Your ship has arrived with the MondoKing 3D. Simply put, the MondoKing 3D is the biggest Therm-a-Rest® mattress ever. Vertical sidewalls create 20% more usable sleep surface so you have room to sleep like starfish. Dual valves allow compressible foam core to expand and inflate quickly when unpacked. A new and improved stuff sack with easy-carry handle is also included.
  • Comfort: 4 in (10 cm) of stabilized loft provides the comfort of home anywhere.
  • 20% More Sleep Surface: Vertical sidewalls maximize useable sleep surface.
  • Incredibly Warm: Foam core delivers all-season warmth to assure a great night's rest anytime.
  • Self-Inflating: Dual valves allow compressible foam core to expand/inflate when unpacked; just a few breaths top it off to your ideal firmness.
  • Mateable: Mates perfectly with another 3D mattress.
USA*Built of the Finest U.S. and Global Materials
L XXL
Color Blue Depths Blue Depths
Style No No
R-Value 11.4 11.4
Color Family Blue Blue
Weight (Standard) 88 oz 108 oz
Weight (Metric) 2497 g 3064 g
Width (Standard) 25 in 30 in
Width (Metric) 63 cm 76 cm
Length (Standard) 77 in 80 in
Length (Metric) 196 cm 203 cm
Thickness (Standard) 4.0 in 4.0 in
Thickness (Metric) 10 cm 10 cm
Packed dimension (Standard) 7.0 x 26 7.0 x 31
Packed dimension (Metric) 18 x 66 18 x 79
Top fabric type 75d Reverse Diamond 75d Reverse Diamond
Bottom fabric type 75d Polyester 75d Polyester
Foam type Urethane Foam Urethane Foam
Country of Origin USA*Built of the Finest U.S. and Global Materials USA*Built of the Finest U.S. and Global Materials
Volume (Standard) 7700 cu. in 9600 cu. in

Documents and Instructions

Click here to download the Universal Therm-a-Rest Mattress Repair Instructions, including how to locate leaks and make repairs in the field or at home on any mattress model.

If you have further questions about repair or warranty, or would like to send your mattress to us for repair. In the U.S., please contact our Customer Service department at 1-800-531-9531. For worldwide service and repair contact information, please click here.

Should you find yourself without access to Therm-a-Rest Repair Kits, repairs can also be made using items commonly found at most outdoor gear shops. (Remember that for maximum effectiveness, ALL of the below repairs should begin with a clean and dry mattress. An alcohol swab is an ideal cleaner that dries fast.)

  • Small leaks not requiring a patch: A urethane-based glue should be used. Some popular brands are SeamGrip® and AquaSeal. Apply a small dab, large enough to completely seal the hole, and allow 24 hours for drying. If your mattress fabric is relatively smooth like the NeoAir or Trail mattresses, peel-and-stick bicycle tube patch kits are an option offering instant repair.
  • Larger holes and tears: All mattresses can be repaired with a self-adhesive fabric patch—like those used to repair jackets and tents. These are commonly found in outdoor gear shops. Cut the patch in a circle to generously cover the hole. Apply a small amount of urethane-based glue to the back of the patch and the area to be covered on the mattress. Apply patch and press firmly. Wipe away excess glue from edges and allow 24 hours to dry.

If you’re not comfortable making the repair yourself and have some time before your next trip, call our service department at 1-800-531-9531 for instructions on sending your mattress back for repair.

Video: Repair Your Therm-a-Rest Mattress

Yes. A Therm-a-Rest Valve Replacement Kit will replace all metal and plastic mattress valves. Instructions for the kit can be found here.

Repair Your Therm-a-Rest Mattress
Repair Your Therm-a-Rest Mattress

Roll the mattress up to force the water out of the open valve. If there is a lot of water, you may have to do this several times. Hang the mattress upside down with the valve open in a warm, dry place. It will take about three days for the mattress to dry out.

Regular cleaning will extend the life of your mattress, especially if you sleep in direct contact with its surface.

Do not put your mattress in the washing machine. Cleaning with a hose or in a bathtub is best. Do not forget to close the valve while washing. For general cleaning, a quick scrubbing with Formula 409®, BioClean All-Purpose Cleaner, or other general household cleaner is best.

Therm-a-Rest mattress care
Therm-a-Rest mattress care

For tree sap, spot clean with a cotton rag soaked in rubbing alcohol. This will take some work and sap will likely leave a stain. However, a dusting with talc or baby powder when you are done should eliminate any residual stickiness.

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freebird919
October 17, 2016
Yes, I would recommend this to a friend
Old camper meets nights rest...finally
Top quality sleep. Needs a little tougher construction.
Braaap
September 19, 2016
No, I would not recommend this to a friend
Mondo zzzzzz's
Used this on a week long climbing trip. Zzzzz! Felt strong every day.
Alex8
September 18, 2016
Yes, I would recommend this to a friend
Tremendous
My work schedule for the summer involved car camping 5 days a week. Last year I made do with my old thermarest prolite backpacking pad. This year I upgraded to the Mondoking and it was just fantastic. I spent a while agonizing about which mattress to get and I made the right call. This pad is very similar to the exped megamats but more affordable and just as comfortable. In contrast to the dreamtimes, this pad is all pad and no memory foam layer (meaning the pad itself is thicker than the pad within either dreamtime). That's fine with me; it's warmer and if you ever felt the need to make it even cushier you could add your own zippered sheet and memory foam topper. I have serious doubts you will need to however; I slept like a baby all summer. Light sleeper, side sleeper, out like a light every night (I've slept close to 50 nights on it since the spring). We have a futon and a queen air mattress at home for guests, but this is what I encourage them to sleep on instead nowadays. Bought one for the girlfriend too. The morning after our first night out she said she had gotten up to use the bathroom and had temporarily forgotten we had gone camping she was so comfy. It does take a while to self-inflate and the side material seems slightly weaker than the top and bottom. Unlike their backpacking pads, this is a thermarest that I allow to self-inflate. It turns out that once it does it's just about perfect firmness for me. Very happy with the purchase. You will find yourself overcome with the desire to show it to your friends and make them lie down on it.