The Black Diamond 9451 is a kevlar lined insulated rubber boot w/ tibia guard and lug sole. The Black Diamond Comfort Fit Form ("Last") used to construct these boots has been designed for maximum comfort and accurate fit. In addition, the Enersole System includes a high-density polyurethane midsole that absorbs energy. The second layer of comfort includes an Ortholite breathable polyurethane footbed that provides all-day comfort. The footbed fabric cover absorbs perspiration and is removable for fast drying.