AMERICAN BUILT with materials from around the world. KEEN.Dry waterproof breathable membrane. Integrated PU heel cushion. TPU shank for midfoot support. Cleansport NXT(TM) for natural odor control. Locking metal hooks and lacing eyelets. Meets ASTM F1677-96 MARK II non-slip testing standards. Meets ASTM F2412-11 and F2413-11 M I/75 C/75 EH standards.