Sea to Summit Ether Light XT Insulated ASC Sleeping Mat is Extreme air mat redefines lightweight cold-climate sleeping comfort through its innovative design and high-quality materials. The mat's 100 percent Nylon with TPU Lamination fabric, paired with 100 percent Polyester insulation, provides a durable and thermally-efficient sleeping surface. The key to its exceptional performance is the loop baffle Air Sprung Cell construction, which creates larger air pockets by positioning the top and bottom fabric layers further apart. This design delivers enhanced cushioning and comfort, particularly for side sleepers without compromising on weight.