The Prolimit Hydrogen unisex polar boot is our warmest boot on the market. The neoprene is 6mm thick and has Zodiac plush lining on the inside. The natural rubber reef sole makes you feel like you are walking on bare foots. Straps attached to the ankle to adjust fitting and reinforcements on the heels make this the perfect boot for hardcore riders who like to go out on the water in winter. The neoprene is 6mm thick and anti-allergic.