7.5-ounce 93% polyester/7% elastane smooth-faced/channeled fleece back - 6.5-ounce 96% polyester/4% elastane panels - Original Fit - WickWork technology forces the transfer of moisture away from the skin to the outside of the fabric where it can evaporate - Smooth-faced channeled back fleece for maximum warmth without bulk - Heavy-warmth fabric in body and lighter-warmth fabric in side panels and arms for maximum breathability - Superior wicking and odor resistance - Flat-lock seams - Integrated thumb holes