The Viking Miner 49er Metatarsal Steel Toe Rubber Safety Boot is designed for safety and comfort in tough workplaces. With its SBR blended NR upper and cotton canvas lining, this boot is highly chemical resistant, allowing you to work with confidence. Its air-cushioned NBR lug sole is slip-resistant, heat-resistant, X-capable, and exceeds a 305K flex rating, making these boots some of the most flexible and capable on the market. Not only that, but it's also sodium cyanide resistant up to 30% concentration. With Achilles tendon and ankle protection, as well as hang holes on the sides and 14" of tall height for added comfort and protection.