SIZE - Medium fits for 56-58CM, 7-7 1/4, 22"-22.8". With an adjustable drawstring built in sweatband to help find the best fit. FOLDABLE: folds up easily, compact and perfect as a fishing or travel hats. DETACHABLE CHIN STRAP: adjustable for a better fit; won't blown off when it gets windy. SPF 50+: this sun hat has passed UPF 50+ test, it could block 97.5% or more of sun UV rays. WIDE BRIM: measures 4 - 4.5" in length, large enough to shade forehead, eyes and cheeks from sun uv ray. The shape looks really adorable.