The Hot Chillys Men's Peach Skins Roll T-Neck combines the soft, light feel and strength of microfiber polyester with an interlock construction to give you warmth without weight and freedom of movement. Interlock knitting is like having a double layer since the two sides are technically knitted the same allowing more space to trap air and more stretch than a flat surfaced fabric. The Hot Chillys Men's Peach Skins Roll T-Neck is made it light for layering.