This set of five medium-sized short sleeve shirts is designed for active men seeking reliable performance wear. Crafted from a blend of 92% high-quality breathable polyester and 8% spandex, the crew neck tops feature four-way stretch and a body-hugging fit for all-day comfort and unrestricted movement. The fabric includes quick-dry technology that rapidly wicks away from skin to regulate body temperature, plus UPF50+ sun protection to block 99% of harmful UV rays. The shirts offer support to reduce vibrations and support -workout, plus a warming effect to keep active during activity. They run slightly small, so choose the next size up if you are between measurements, and wash dark and light fabrics separately to preserve quality.