KM Women Outdoor UV Protection Sun Shade Wide Brim Sun Hat Beach Hat With Ponytail Opening M Main material: Soft and breathable nylon. The fabric is windproof, easy to clean and quick dry. Adjust the head girth by the bowknot, beautiful and practical. Adjustable Velcro strap for a custom fit. High quality brim, environmental and 3mm thickness, easy to roll up. 100% UV protection and waterproof. Size: M: Head girth 22.8", fit for 21.7"-22.8". We have two different styles hat, the ponytail sun hat for long hair and the sun hat for short hair.