Coolibar UPF 50+ Women's Chlorine Resistant Bucket Hat - Sun Protective 100% Polyester Hook and Loop closure UPF 50+ - protects against 98% of UVA and UVB rays Aqua SUNTECT&reg;: Chlorine and saltwater resistant with 4-way stretch Adjustable Velcro strap at center back for a custom fit; Floats in water Approx. circumference: 22 3/4 inches (S/M), 23 5/8 inches (L); 3 inch brim; Easy care: hand wash, line dry; Imported Recommended for your days in the water, at the pool, lake or ocean - great for leisurely lap swims or water aerobics