The lightweight, breathable Outdoor Research® Swift Cap will have you feeling cool and protected. Full mesh liner crown for added ventilation. TransAction™ headband wicks away moisture. Adjustable quick-release back strap for sure fit. Nylon panels that offer UPF 50+ sun protection. Shaped bill. Machine wash cold and drip-dry. 100% nylon. Imported. WARNING California's Proposition 65 Product measurements were taken using size One Size (7 1/8-7 5/8). Please note that measurements may vary by size. Measurements: Circumference: 23 in Brim: 2 3⁄4 in View Zappos.com Glossary of Terms Outdoor Research Swift Cap