1.Moisture-wicking and quick-dryingMoisture-wicking material and mesh design can easily wick away sweat and dry quickly in hot summer. Our skull caps are made from skin-friendly fabrics that will give you a baby-like soft touch when worn. 2.UV/UPF50+ ProtectionOur cycling cap can protect against sun and UV rays in hot summer days and protect your skin from sunburn when outdoors. Cycling cap is made from 88.7% polyester, 11.3% spandex. The skin-friendly icy material provides a cool feel and is so light you'll hardly notice this hat. 3.Lightweight and DurableArcweg Helmet Liner Cap is soft and lightweight, easy to put in your pocket after use. High quality sewing makes our skull cap's sturdy and stretchable fabric that resists wind, dust and dries quickly. Repeatable hand or machine wash without shrinking or warping. 4.Universal SizeOur helmet liner cap has high elasticity. Does not put any pressure on the head, easy to wear and adjust. One size fits most adults and children, fits snugly on the head, and is comfortable to wear on a helmet, hat, or on its own.