Lameda Men's Compression Shirt Running Athletic Fitness Workout Tops Base Layer Short Sleeve polyester Imported Fabric: 90% Polyester, 10% Spandex. Excellent elasticity with enhanced range of motion. Powerful, lightweight and designed to provide unrestricted freedom. Raglan sleeve construction for unrestricted movement. Flat lock seams to reduce chafe for greater comfort. Perfect for sports such as running, crossfit, strength and ball sports.