Under armour Compression mock. Signature under armour compression fit for top performance. Updated brushback knit fabrication traps heat for enhanced warmth. Flatlock seams and raglan sleeve construction for increased comfort and mobility. Ergonomic neck design to keep more of your neck covered for added warmth. Silicone gripper at the hem to keep your shirt from riding up and letting cold air in. New updated locker tag. Superior moisture transport keeps you dry and comfortable.