Size: one size fit most. Adjustable size: 57-59cm 22.4-23.2, This Wide Brim UV Sun Hat with a bowknot around the straw hat crown make the hat more chic. . Adjustable cord inside the sweatband. This beach straw hat offer high UV UPF sun protection with full brim, sun blocker function make the hat perfect to use as a beach hat for holidays as a daily head wear , is very wearable with anything like dress, bikini or shorts . . Cotton . Fastening: Buckle . Floppy . SPF : Passed UPF 50+ test, the 3 wide brim could block most sun UV rays. Protect your face and eyes from the hurt of the sun. . Windproof Belt: The sun UV protection hat has a windproof belt is not easily blown away by the wind. And the hat also has a locking buckle, which helps it easy to adjust and fix it . A Foldable Summer Hat,it's easy to carry no matter in bag or suitcase for travel or holidays .