A sustainable alternative to traditional neoprene, petroleum-free Terraprene neoprene is made from limestone and recycled tires. Constructed with 3 mm thick neoprene upper for maximum warmth with a 3 mm neoprene insole for added comfort. Reinforced at the toe and heel for long-lasting durability. Constructed with 3 mm thick neoprene upper for maximum warmth with a 3 mm neoprene insole for added comfort. Cush graphene-infused interior provides thermal-conductive properties for more warmth while also reducing water retention. The HydroCuff hugs the ankle tight to prevent excess water from dripping in. Features an ankle pull tab to help slip the bootie on and off. A playboater's go-to bootie, the lightweight NRS Freestyle Wetshoe is crazy flexible, perfect for fitting into tight boats. Plus, a naturally shaped toe box and high-rise design provide additional comfort and protection for all-day boating.