New, Unused, 27cm Mutant 4 Firewall These 4mm thick socks are designed for cold weather, utilizing FIREWALL, which offers excellent stretch, flexibility, and quick-drying properties. They provide a comfortable fit, gently holding the entire foot, and feature a three-dimensional design that follows the movements of a surfer. The AFW-830A3 uses FIREWALL28 (yellow), while the AFW-830A2 uses FIREWALL27 (blue). Color: Black Material: Main body 5x4mm thick Ultra Flex Cryptojersey/FIREWALL28, Sole Rubber sole Size: 27cm