The Nike Dri-FIT Club Cap is a performance-oriented hat, available in structured or unstructured designs, that features Nike's Dri-FIT technology to wick sweat, keeping the wearer cool and dry during activities. These caps are typically made from recycled polyester, offer features like eyelets for ventilation and a tri-glide or hook-and-loop closure for adjustable fit, and are suitable for sports like running, golf, and tennis. S/M size fits Fits a head circumference of 21 1/4" - 22 3/8" (Hat size 6 3/4-7 1/8)