The Merino Lined 7mm Hood is the warmest wetsuit hood available, and will keep a diver's head warm and comfortable in even the mostsevere water temperatures. Constructed from 7mm titanium lined neoprene throughout the head and neck areas, with Pinnacles patented Merino lining throughout. Merino lining adds up to 35% more thermal efficiency then standard neoprene rubber alone. Merion also doesnot promote the growth of bacteria, making it hygienic and reduces odor. The hood is equipped with a 3mm face seal with smooth skin seal can be trimmed to custom fit the face mask seal. Hood has an automatic vent that allows air to escape as necessary from the topof the hood while restricting water to re-enter.