This is the lightest, most breathable fabric available. You will feel like you aren't wearing anything. It is borderline mesh, but also features a UPF sun protection rating of 30.
Men’s and Women’s Running shirts are designed to have a Relaxed Running fit, with 1-2” of ease. The fabric has a 4 way stretch allowing it to fit next to and move with the body in motion.
Men's - Crew Neck
Women's - V neck