Description Alpha Construction: Built with hand-laid premium, natural rubber over insulating neoprene for durability, flexibility and complete waterproof protection. Air-Circ Liner: Quick-drying mesh that circulates air inside the boot when you walk, keeping your feet cooler, drier and infinitely more comfortable .Alpha Fit: Alpha Fit provides half sizes and multiple widths for a comfortable, precise fit. Kick-Off Heel Plate: For easy hands-free removal. Foredeck Outsole: This slip-resistant outsole is versatile and designed to provide traction in the wettest environments.