SIZE: S: suitable for head 35-45cm; M: suitable for head 45-55cm; L: suitable for head 55-65cm; XL: suitable for head 65-75cm; COMFORTABLE FIT: this diving cap made with 3MM or 5MM premium neoprene to give you a flexible and comfortable fit, you will have less restrictions during in the water, offer you a comfortable diving experience Long-Lasting Warmth: Specially designed for both underwater and surface watersport activities, our hood offers all-day comfort! A large bib tucks easily into wetsuits and is available in differen thicknesses, your covered for warm, moderate and cold-water use Maximize Performance: This wetsuit Dive cap Provides protection from harmful UV rays and aquatic stings.The unisex hood Keeps warm for your head and neck with quick drying and easy put on and take off Wide Application: The extreme comfort and high breathable materials can be used for sun-resistant, bind hair and moisturize etc, wonderful for beach, snorkeling, swimming, scuba diving, surfing, sailing, kayaking, canoeing, ect. Durable 3D head guard design:High stretch and excellent recovery, glued and blind stitched for superior strength and durability that will last, dont worry about ripped, 360 full protection of all parts of the head .