The Waterproof H1 HV Polar Hood is a 5/10mm hood with high visability colours & reflective patches so you can be seen on the surface & underwater easily. Thick neoprene keeps your head warm in the coldest waters & thinner sections allow movement. Hi Vis The orange colour contrasts against blue & green water well so you can be seen from a distance on the surface & underwater. Reflective patches around the head reflect light to further increase your visibility in the water. H.A.V.S. The top of the hood also features Waterproof's dual layer Hood Air Venting System, HAVS, that allows expanding air trapped in the hood to escape out of the top of the hood without letting water in Specifications 5 / 10mm Neoprene * Please note this product isn't waterproof, the brand name is Waterproof, you will get wet