Billabong Furnace 3MM Split Toe Wetsuit Boots Black - Unisex with Furnace Thermal Lining - Drymax Cuff The Furnace is Billabong's premium cold-water wetsuit series, designed specifically for warmth and comfort. The Furnace 5mm boot is made of the most advanced materials and construction techniques. Drymax cuff EZ-on pull tab. None marking grey gum sole. Flex cut arc. Durable arch bridge. Internal split toe Furnace lined