The water- and wind-resistant neoprene exterior of the Proof™ shoe covers are optimized with Flex Zones in key areas, engineered from a super stretch neoprene that minimizes bulky feel without compromising warmth. The interior is fleeced with anti-microbial X-Static® AGrid™ thermal fabric which utilizes silver fiber to hold heat, further enhancing the insulating power of neoprene. Reflective detailing and durable walking pads are the finishing details in this winter essential.