The Rainier has a direct-injected PU midsole,a dual-density, Aglon-treated, CMEVA-covered wave footbed, and full length Receptor Technology. It is a great looking sandal for the everyday adventurer and massaging waves keep you comfortable all day long. It also features a rubber outsole, stretch-fit lining, and superb flexibility with great shock absorption and comfort for every adventure. The upper is made of nubuck.