The Inertia Ozone is Klymit’s minimalist sleeping pad offering. Its unique design aims to eliminate extraneous material and lower the weight of the product by cutting strategically placed holes throughout the body of the pad. This is an interesting concept, since many other manufacturers cut weight by making the pad shorter, either for a smaller person or for a ¾ length pad. The Inertia Ozone is a full-length pad with an attached pillow, but manages to stay at a competitively low weight and small size and at a notably lower cost than many of the other lightest sleeping pads.

Weight

Klymit claims that the Inertia Ozone is a fast-and-light sleeping pad. But if it is supposed to be fast-and-light, why the attached pillow? Most lightweight and ultralight backpackers are adept at using puffy jackets and extra clothing as a pillow, so it seems strange to include this features on a pad meant for skimping ounces. This pad has large holes cut into it, presumably to cut weight. These holes prevent the pad from having and R-value rating and makes it less warm, which leads us to puzzle further: when going to such an extreme to cut weight that holes in your sleeping mat are acceptable, why include a pillow? Not only does the pillow add the bulk and weight of the extra material, it also adds the weight of a second valve, since the pillow is inflated separately from the body of the pad. We think the concept of leaving holes in the pad to reduce weight is an interesting one, but it seems as if not all aspects were fully considered in the design.  

Klymit’s website claims the weight of the Inertia Ozone at 10.9 ounces. If this was true, it would be the lightest full-length sleeping mat in our lightweight test. However, when we weighed it on our scale in its stuff sack, we recorded a weight of 13.4 ounces, making it heavier than the two other inflatable pads we tested that both came in around 12 ounces, the NeoAir XLite and the Sea to Summit Ultralight Mat. It might have stayed in the 10 ounce range without that attached pillow…

Packed Size

The Inertia Ozone packs down plenty small in a 3.5 x 6 in package. It is comparable in size to other small and packable inflatable pads such as the NeoAir XLite and the Nemo Tensor. We found the Sea to Summit Ultralight Mat to be a tiny bit smaller when rolled, and easier to fit into its stuff sack as well. The Inertia Ozone is difficult to roll well and cleanly with the added square of pillow on the end. If we abandoned trying to fit it into the stuff sack and tucked it in a corner of our backpack without it, we found it was much easier to pack and retained its small status.

Comfort

Despite our criticisms, we actually think the pillow attached to this pad is quite comfortable. Comfortable but unnecessary. It was a luxury to have a cushion for the head pre-made and pre-placed so we didn’t have to go through the hassle of filling a stuff sack with our extra layers or artfully arrange our backpack underneath our head at night. For the campers that always bring an extra inflatable pillow along with them, this pad has an obvious benefit. It is difficult to assess whether the attached pillow is lighter weight than popular backpacking pillows like the Sea to Summit Aeros Pillow, but it is more convenient and in many ways more comfortable to have it already attached.

However, the rest of the pad was not as comfortable as we had hoped. The pad is designed with inflated rails that cushion and protect a sleeper’s body at all the important pressure points. In between these rails are holes open to the ground, and these holes are shockingly large: a couple of inches square. For back sleepers, this mapped rail system works well, and in fact is surprisingly more comfortable than anticipated. But the moment we rolled on our sides, we felt our hips digging into the ground and were no longer adequately supported. Our testers felt that even the thin closed-cell foam mats like the Big Agnes Third Degree and the Therm-a-Rest ZLite were more comfortable than the Inertia Ozone for side-sleeping.

Warmth

Since this pad has significant holes incorporated in the design, it can’t be rated for R-value. In practice, we confirmed that it is not as warm as the lightweight pads with high R-values, such as the NeoAir XLite, the Therm-a-Rest ZLite, or the Therm-a-Rest ProLite. It is comparable in warmth to the lower R-value Sea to Summit Ultralight Mat (0.7 R-value) and the thin Big Agnes Third Degree, which does not have an R-value rating. The lack of a continuous barrier between the sleeper and the ground means that this pad is best for summer, low altitude trips, and it would not transition well  to three-season or high mountain backpacking or camping.

Durability

The Inertia Ozone is plenty durable for camping on rough surfaces without a ground cloth. The bottom of the pad that contacts the ground is made with burly 75-denier polyester, while the top is constructed from lightweight 30D polyester. D, or denier, indicates the density of the individual fibers in a material. The higher number corresponds to heavier and burlier fibers for a given length. 75D polyester is more substantial than any other material used on an inflatable pad in this test. We found that we had very little worries that this pad would pop or break.

Ease of Use

The benefit of this thin pad is that it is extremely easy to inflate. It only requires about 4 breaths to fully inflate the main body of the pad, and then a few more to inflate the pillow. We found this to be a great relief when compared to the blue-in-the-face inflation required by other air construction pads like the NeoAir XLite and the Nemo Tensor. The pillow does require a separate inflation process, which complicates the ease of use somewhat, but the breaths required to inflate are still minor. Where the ease of use score suffers is in the repacking. The floppy de-inflated pad and the strange shape of the pillow make it difficult to roll up and store back in its stuff sack. We found it was much easier to fold and roll and store in our backpack without the stuff sack, which decreases the weight also.