KEEN.DRY waterproof, breathable membrane. KEEN.KEY-TECH FLEX: contoured underfoot support provides structured stability and comfort. Contoured heel lock. Reflective webbing for additional safety and visibility. Built on a woman's-specific last. Meets ASTM F1677-96 MARK II non-slip testing standards. Meets ASTM F2913 SATRA non-slip testing standards. Cleansport NXT(TM) for natural odor control. MEETS ASTM F2892-11 AND F2892-17 EH standards.