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Klymit Inertia X Frame Review

Men's Sleeping Pad

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Price:   Varies from $55 - $72 online  —  Compare at 2 sellers
Pros:  Weighs just 9 ounces! Packs down ridiculously small
Cons:  Uncomfortable, not warm, air pump and pump valve add unnecessary weight
Editors' Rating:     
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Manufacturer:   Klymit


The Klymit Inertia X Frame is an innovative ultralight air core sleeping pad that uses baffles in key places to keep you off the ground and save weight. The pad is the lightest and most compressible "full length" pad we tested. It weighs a mere 9.1 ounces and can fit in your back pocket when rolled up.

Although the X Frame is impressively lightweight and compact, it has several drawbacks that restrict its use to a specific group of people. 1) The pad's air baffles are "body mapped" to fit someone about 5' 10" in height. Depending on how your body parts match up to it, the pad may not fit you. The pad is also the narrowest of the 20 we tested it's 18" wide as opposed to the standard 20" width. Thus, wider people may not fit on it. 2) The pad is ideal for people who sleep on their backs and don't thrash about at night. You may not find the Inertia X Frame to be comfortable if you turn over frequently, sleep on your side, or curl excessively. 3) The pad's thin baffles and large open spaces do a poor job at insulating you from the ground below; the pad is best for summer use. In sum, the Inertia X Frame could be a good choice for summer backpacking if you're around 5' 10" and sleep on your back.

Our top rated ultralight pad is the Therm-a-Rest NeoAir XLite, which weighs 12 ounces in the 72" x 20" size. The NeoAir XLite is more comfortable, warmer, and more versatile than the Inertia X Frame. If you're counting ounces, we suggest the NeoAir XLite in size small (47" x 20"), which weighs only eight ounces (put your boots and backpack under your legs).

RELATED: Our complete review of men's sleeping pads

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Analysis and Hands-on Test Findings

Review by:
Jeremy Bauman
Review Editor

Last Updated:
January 17, 2016
The Klymit Inertia X Frame is designed with the ultralight backpacker in mind; however, it isn't very versatile and isn't comfortable. Buy it if you want one of the lightest full-sized pads on the market and don't mind a loss in comfort or warmth.

Performance Comparison

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While other pads eliminate weight by removing foam or using lightweight materials, the X Frame takes an aggressive weight savings approach by eliminating portions of the pad itself.


For an inflatable sleeping pad, this one is amazingly uncomfortable. When used side-by-side with other competitors, our testers found this pad just as uncomfortable as foam pads like the Best Buy winning Therm-a-Rest Z Lite SOL and the Therm-a-Rest Ridge Rest SOLite. Unfortunately, the X Frame's unique and aggressive design doesn't lend itself to comfort in the slightest. Unless you lay on this pad perfectly, you will feel the ground. Sleeping on your back seems to be the most comfortable, but we would not recommend this pad if getting a goodnight of sleep is a priority.

The Inertia X Frame comes with a hand pump that allows you to inflate the pad beyond what's possible by mouth. Our testers found this to be unnecessary because an adequate pressure can be achieved without using the pump.

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Here you can see how the X Frame is mapped. The mat is most padded around your hips and shoulders along with some small baffles for your feet.


Low weight is the biggest reason to purchase this pad. The regular size we tested weighs a scant 9.1 oz before the weight of the included hand pump (we didn't like using the hand pump because blowing it up with our mouths seemed adequate). The small version (Inertia X-Lite) weighs just 6.1 ounces! While it is incredibly light, we think the abysmally low comfort score is too great a price to pay. In our opinion, cutting holes in a pad is a poor way to save weight compared with simply reducing the length and using a pack for your feet. For instance, the size small Therm-a-Rest XLite weighs just 8 ounces, making it lighter than the X Frame, much more comfortable, and warmer. The X Frame is meant for those who need to shave every last ounce off their kit and don't mind sacrificing comfort.


With an R-value of 1, this pad is among the least warm in this review along with the Big Agnes Air Core and the Sea to Summit Ultralight. If you're sleeping directly on snow, expect to be really cold.

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The hollow portions of the pad allow your sleeping bag to loft into them. The idea is that your sleeping bag will help insulate you from the ground. However, we did not find this pad to be very warm in practice. It is best used in summer.

Packed Size

This pad packs down about as small as a can of soda so you won't notice it in your pack. The next smallest pad was the Sea to Summit Ultralight, which is about twice the size of the X Frame.

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The X Frame is ridiculously small. It is half the size of the next smallest pad we reviewed. Buy this product if saving space is a priority.


The top and bottom of this pad are made with 30 and 75 denier polyester respectively. During our testing, we didn't note any issues regarding durability.

Best Applications

Without question, the best use for the X Frame is ultralight thru-hiking. If your goal is to strip every possible ounce off your base weight and reduce the size of your pack, this sleeping pad is worthy of your consideration. However, the vast majority of our testers prefer to spend a few ounces and upgrade to the more comfortable Therm-a-Rest XLite. That said, if you're set on a minimalist hiking style, pick up the X Frame and crank out the miles.


Typically, ultralight backpacking equipment costs a premium but not so with the X Frame. Retailing for just $72, you can lighten your pack without lightening your pocket book. Keep in mind that this is a specialized piece of gear that really only works well for ultralight backpacking and it's not very warm. If you're looking for one pad that'll work for car camping and general backpacking, we'd recommend a more comfortable pad like the Therm-a-Rest X Lite or Sea-To-Summit Ultralight. Alternatively, if the low price tag is appealing to you, consider one of our Best Buy winning pads: the Therm-a-Rest Z Lite SOL or the Therm-a-Rest NeoAir Venture.


The Klymit Inertia X Frame is an ultralight pad for hikers wishing to purge their packs of every possible ounce. The biggest downside to this pad is the lack of comfort and warmth as it is quite thin and has a low R-value. Similarly, it packs down ridiculously small so you won't even notice it in your pack. Though we appreciate that gear companies continue to innovate and make gear lighter, the X Frame does so at the expense of comfort and we think that weight is best saved in other ways--namely by using a two-thirds length pad.

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While you can obviously use this pad outside your sleeping bag, you can also put it in your bag. Doing so will keep you perpetually centered on the pad.

Other Versions

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Klymit Insulated Static V Lite
  • Four Season sleeping pad
  • 19.6 oz
  • 4.4 R-Value
  • $100

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Inertia X-Lite
  • One of the lightest 3/4 length pad on the market
  • 6.1 oz
  • $62

Jeremy Bauman

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OutdoorGearLab Member Reviews

Most recent review: January 17, 2016
Summary of All Ratings

OutdoorGearLab Editors' Rating:   
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