The Billabong Furnace Ultra is the pinnacle of the Furnace range, a wetsuit built with Billabong's most advanced materials and construction for surfers who want the very best. Like the wider Furnace lineup, the Ultra is built using Ocena natural rubber rather than traditional neoprene, combining 85% Hevea rubber with Bolder Black and soybean oil for a 100% neoprene-free construction that is lighter, stretchier and better for the environment.