The Oofos OOahh Sport Flex in OOMatte Black takes all the comfort, cushioning and protection from the original, and adds in an adjustable strap, letting you achieve the optimal fit for each foot. Like the rest of the Oofos range, the OOah Sport Flex provides instant comfort, shock absorption and stress reduction so that you will want to put nothing else on your feet after a long run. OOfoam Absorbs 37 more shock than other materials, Reduces stress on sore feet, knees and lower back, Closed cell foam is machine washable and designed to minimise odour, Cradles your arches, Enables a more natural motion. The Oofos OOahh Sport Flex Sandals feature an adjustable velcro strap for an optimal stay-put fit. Features: OOfoams - Absorbs 37% more shock with every step than traditional footwear foam. Reduces Stress On Sore Feet, Knees and The Lower Back - Provides the feet with relief and a chance to recover. Cradles The Arches - Designed with tremendous arch support to take the pressure off. Biomechanically Design For Natural Motion - Flexes with both your foot and the ground which enables your foot to articulate the way nature intended. Moisture and Bacteria Resistant - Doesn't retain the smell. Adjustable Velcro Strap - For an optimum fit. Durable OOfoam - Holds its cushion. Shower/Beach Ready. So Light They Float! Machine Washable.