Baleaf Men's Compression Base Layer Running Shirts 90% Polyester, 10% Elastane Ultra-soft and breathable fabric with a compression fit provides superior comfort Four-way stretch construction brings fantastic flexibility for maximum freedom of movement Sweat-wicking fabric mesh underarm panels delivers ventilation and keep you dry Ergonomic flat-seam construction for extra comfort to help minimize chafing Reflective logo painted to ensure safety at night