The original, thicker HeatGear(R) fabric helps keep you protected under your gear - limiting pinching, snagging and chafing. Fit & Design: Tight fit shirt Light and tight fit delivers optimum muscle compression so you can sense where your body is in space 4-way stretch material moves better in every direction Ergonomic flatlock seams deliver a comfortable, chafe-free fit Mock neck for added coverage Technology: Material wicks sweat and dries quickly to keep you comfortable