Imported UPF 50+ UV PROTECTION – it could block 97.5% or more of sun UV rays. FOLDABLE & PACKABLE – could be folded up easily into any suitcase, perfect for travel or beach Vacation. 3.7WIDE WIRED BRIM: large enough to supply great sun uv protection effectively. Optional CHIN STRAP: adjustable neck cord, exceedingly useful for windy days 3 ADJUSTABLE SIZES: Small: 54-55CM 21.2-21.6; Medium: 56-57CM 21.8-22.4; Large: 57.5-59CM 22.6-23.2. Adjusts via inner tape in the sweatband.