Seac Sub Python Plus Super-Elastic Extra-Flex Jacket and John 5mm Wetsuit Outer lining: Super-elastic Extra-flex nylon of the latest generation. Inner lining: smooth, open cell cross-section Cutting-edge neoprene to ensure the highest possible level of elasticity. Closing system for wrists, ankles, and face in ssRs (smooth skin Round seal). plenty of reinforced sternum protection with protective cushions in neoprene.