Bringing classic military style right up to date, the BUFF Rinmann Military Cap is made with mechanical stretchable fabric, with an inner sweatband to absorb your perspiration. It\'s very comfy, very light, and blocks out 98% of the sun\'s rays.Flexible self-adjusting fit  (no straps!) Inner sweatband at front side UPF 50+ (98% UV Protection) Weight: 59g Crown and brim: 90% Polyester 10% Elastane Inner sweatband: 100% PolyesterSize S/M: 55.5cm Size M/L: 57.5cm