The Therm-A-Rest ProLite Plus Lightweight Year-Round Sleeping Pad for cold-weather backpacking and camping is an ultra-compact winter expedition sleeping solution, adding a critical padded layer of warmth between sleeping bag and ground in cold conditions. Featuring diagonal-cut foam, which offers more warmth than the typical vertical-cut foam, the expanding core is lightweight and compressible for easy packing. With an R-value of 3.4, it's ideal for sleeping outside in any season (R-value measures the material's ability to insulate; the higher the R-value, the warmer the sleeping pad). The mattress pad self-inflates, and can easily be adjusted for firmer support with a few breaths into the valve. The four-season Therm-A-Rest ProLite Plus Winter Air Mattress is perfect for ski touring and alpine excursions. Available in three sizes: Small measures 47 x 20 x 1.5 inches, packs to 11 x 4 inches, and weighs 16 ounces; Regular measures 72 x 20 x 1.5 inches inflated, packs to 11 x 4.8 inches, and weighs 23 ounces; Large measures 77 x 25 x 1.5 inflated, packs to 13 x 5.1 inches, and weighs 31 ounces. Stuff sack included. Manufacturer's limited lifetime warranty. Made in the USA.