This is the Sharkskin Chillproof Hood Thermal Layer for Scuba Diving, Snorkeling etc. Features: More than 25% of body heat is lost through the head and extremities of the body The hood design provides the best insulation and protection for cold dives and activities It can even be worn under a conventional neoprene hood for extra warmth, and is flexible enough to slide off if required and still be comfortable Size - FOREHEAD XS: 46.5 - 48.5cm S: 49 - 51cm M: 51.5 - 53.5cm L: 54 - 56cm XL: 56.5 - 58.5cm 2XL: 59 - 61cm 3XL: 61.5 - 63.5cm 4XL: 64 - 66cm Sharkskin Chillproof is an aquatic specific, windproof 3-layer composite material that has been developed for water sports athletes. The comfortable micro fleece layer is next to the skin and wicks moisture and sweat away from the body to help keep you dry. The second middle technical layer is 100% windproof yet breathes to regulate body temperature while stopping windchill. The third outer layer is a nylon/lycra blend for abrasion resistance and 4-way stretch. It is also UV resistant for sun protection and has a durable water repellent finish (DWR) to provide a protective shell that sheds water. Sharkskin Chillproof is neutrally buoyant, anti-microbial, odour resistant, itch resistant and machine washable. PERFORMANCE GUARANTEE Authentic Sharkskin garments come with a 12-month guarantee on workmanship. Excludes fading and degeneration as a result of excessive exposure to chlorine or sunlight. We guarantee Sharkskin will perform as advertised.