2XU Flex Running Compression Arm Sleeves 100% Other Fibers Imported PWX power compression supports arm muscles for better performance The graduated fit improves blood flow for faster warm up and recovery Flexibility in the elbow adds comfort and range of motion Antibacterial and moisture-wicking properties keep sweat and odors in check Ideal for wearing during and post-workout or while rehabbing from injuries, 80% Nylon/20% Lycra