The T5MO Tilley Hat, designed with a medium brim, is made of a soft, sueded certified organic cotton with ¾" polyester mesh. The mesh helps to both ventilate warm air out and allow cooler air to flow in while the sturdy cotton fabric is rugged yet exceptionally lightweight. Features: Guaranteed for life not to wear out Insured against loss Excellent sun protection, rated UPF 50+ Dark underbrim for glare protection Repels rain, floats Ties on in the wind Machine washable, won't shrink Secret pocket Medium brim with ¾" ventilation mesh