UPF 50 Rated Paper-Straw. FOLDABLE: soft straw fabric, foldable and packable for travel. DETACHABLE CHIN STRAP: adjustable for a better fit; won’t blown off when it gets windy. SIZE – Small fits for 54-55CM 21.2-21.6; Medium fits for 56-57CM 21.8-22.4; Large fits for 57.5-59CM 22.6-23.2. With an adjustable tape built in sweatband to help find the best fit. VENTILATED: perfect for beach vacation, also great for summer rides, fishing and hiking. WIDE BRIM: not only looks stylish, but also wide enough to shade uv rays effectively.