EPIC 3/2 BACK ZIP FULLUltraFlex High performance super stretch neoprene with a durable outer skin that resists velcro pulls and snags. Fluid Flex Firewall Windproof exterior with water wicking interior thermal jersey. Glued and Blind Stitched Seams The GBS construction initially seals the neoprene edges together and then uses a stitch that partially penetrates the neoprene, offering a watertight and highly flexible solution. This is a solid choice for cold water surfing.