Sea to Summit's Ultra Light sleeping mat range has been tuned to give you the lightest and smallest pack-volume mat without compromising on Sea to Summit’s Air Sprung Cell comfort. Their tapered profile and Single Layer construction minimise weight and bulk. Single Layer construction uses a medium resolution cell matrix to gain sufficient thickness for great cushioning and support on uneven ground. It is incredibly comfortable for its tiny pack-size and works well with the Sea to Summit lightweight range of sleeping bags. Despite being a super lightweight mat, the Sea to Summit Ultra Light sleeping mat can be used on uneven grounds and rocks. The Sea to Summit Ultralight Sleeping Mat has what it calls "air spring cells," 225 of them created by spot welding the top and bottom of the mattress. When you shift your weight, this isolates the compression of the pad, in much the same way a coil bed mattress works, and allows it to conform to your body far more naturally.The valve has two modes: When you're inflating the pad, air can only enter, so your breath doesn't come rushing out, but when you deflate it, the large opening lets all the air escape quickly. And the 495 gram, 198 cm by 64 cm Ultralight Large rolls down to the size of a drink bottle.   Features and Specifications Includes an Airstream™ Pump that is integrated into the stuff sack for quick and easy inflation. Air Sprung Cells™ conform to your body shape, providing a more even dispersion of pressure across the mattress for a more comfortable nights sleep The ultra-light range has a single layer of medium resolution cells to give you the lightest and smallest pack-volume mattress. Multi-function valve provides fast inflate, deflate and easy fine-tuning for personalised comfort. Extrusion TPU lamination is vastly superior to roll-to-roll lamination, helping to prevent delamination. Multi-function valve provides fast inflate, deflate and easy fine-tuning for personalised comfort. Length: 198 cm Width: 64 cm Inflated Depth: 5 cm Rolled Size: 7.5 x 20 cm R-Value: 0.7 Weight: 495 grams / 17.5 oz Number of Air Sprung Cells: 225 Includes: Airstream Stuff sack and repair kit    Frequently Asked Questions Q. WILL MOISTURE BUILD UP DAMAGE MY MAT IF I INFLATE IT WITH MY BREATH?A. Absolutely not. We have gone to extreme lengths to ensure that the fabrics and coatings that we have used in the construction of our Air Sprung Cell Mattresses can easily withstand the moisture build up that could occur from inflating them with your breath. We have also carefully treated our internal coatings to ensure that microbial life cannot replicate in a moisture rich environment, thus removing the chance that your mat may become moldy. Q. WHAT’S THE BEST WAY TO INFLATE MY AIR SPRUNG CELL MATTRESS?A. STS Air Sprung Cell Mattresses can be inflated in a number of ways. We have been very careful in using a TPU laminate on the internal face of the fabrics that has been manufactured with an anti-microbial treatment. This means that you are able to blow your mattress up by mouth without risk of mould growth inside the mattress. If you prefer not to huff and puff when setting up camp, we have created the Jet Stream Pump Sack and the Air Stream Dry Sack to make your life easier. Q. HOW DO I REPAIR MY AIR SPRUNG CELL MAT?A. Every mattress comes with a repair kit containing a number of patches. These self-adhesive repair patches can be used on holes up to about 2 mm in diameter with complete confidence. If you have a hold larger than this, please contact STS enquiries as to the best way to effect a repair. Q. WHAT DO I DO IF WATER OR MOISTURE GETS TRAPPED INSIDE MY MATTRESS?A. Having a small amount of moisture trapped inside your mattress is not a major issue, and the moisture will not damage your mat in anyway because of the anti-microbial TPU lining. You should, however, give your mattress an opportunity to dry out when you get a chance. The best way to achieve this is to hang the mat in a warm and dry environment with the valve open. Q. WHAT’S THE BEST WAY TO CLEAN MY STS MATTRESS?A. Mild soap and water is the best way to try and clean any dirt or grime off your mattress. The external coating on the face fabric will ensure that cleaning is quick and effective. Be careful not to use any strong cleaning products or bleaches, as these will damage the fabrics and potentially compromise the integrity of the mattress. Sea to Summit Ultralight Inflatable Sleeping Mat - Large