CW-X Stabilyx Tight Mens 80%Coolmax Polyester/20% Spandex Fit: Compression--Supports your muscles to prevent fatigue during intense training. Anti-Microbial--Anti-microbial treatments provide permanent odor protection by inhibiting the growth of bacteria and mildew in the fabric. UV Protection--Fabric is treated to block UV (ultraviolet) radiation from the sun, helping to prevent sunburn. Ergonomic Cut/Seaming--Seams and/or design lines of the garment follow the body's curves to allow freedom of movement and prevent skin irritation. Flatlock Stitching--Seams are sewn flat to the garment to enhance durability and prevent skin chafing/irritation.