Product description What head sizes does this sun hat fit? Fits head circumferences from 55 cm to 58 cm (≈21.6" to 22.8"). The adjustable rear drawstring lets you customize the fit for a secure, comfortable feel. Does the hat provide proof of the UPF 50 sun protection? It features UPF 50+ sun protection to block 98% of harmful UV rays, with a 3-inch wide brim that provides full shade for your face, neck, and ears. Can this hat be folded and shoved into a backpack without it getting all bent up? Absolutely! With its soft yet structured brim, this hat rolls up easily to fit in tote bags, backpacks, duffels, or beach bags without losing its shape. Is this hat lightweight and breathable for all-day wear? Ultra-lightweight at just 78g (≈2.75 oz). The U-shaped mesh vents on the crown keep airflow high, preventing overheating on hot, sunny days.