Description of Hot Chillys 9859 Solid Zip T Technologically advanced to keep you warm and comfortable ...no matter what you’re doing Hot Chillys has led the performance apparel industry for more than a decade with moisture managing base layer technology. When founded in 1985, Hot Chillys revolutionized the ski market with performance ski "warm wear" (base layer underwear) incorporating fabric technologies previously found primarily in running apparel. Hot Chilly engineers the most advanced performance products possible; test and retest for function and durability, then add two parts fun and a cold cerveza. Cuz if you're not having fun, it's just not worth it! Features: Single sided fleece, 85% MTF nylon, 15% Spandex Moisture transport to keep skin dry and to promote warmth Brushed back/fleeced back for softness and warmth Sleek body fit Plush warmth without bulk Flat seam construction for seam strength and durability Warmth Factor = 9