Sharkskin Women's Chillproof Hooded Vest Scuba Diving Exposure Garment for Scuba Diving, Snorkeling, Surfing, Etc. More than 25% of body heat is lost through the head and extremities of the body The vest with hood design provides the best insulation and protection for colder dives The hood protects against chaffing from mask straps, keeps your head and ears toasty warm, and is flexible enough to slide off if required, while still remaining comfortable