The Waterproof H1 5/10mm Polar Hood has been built for and tested in the most extreme conditions on the planet. Heat loss in these situations can be easily prevented by wearing a thick hood, especially when doing longer dives!
The H1 10mm hood is constructed with I-span superstretch nylon and bonded hi-quality nylon thread. It has double layered 10mm protection in the most important areas to prevent heat loss and the Glideskin seals for neck and face! It has air vents (Waterproof's Hood Air Venting System) with one way valves to prevent air build up.