Upgrade your shoes with Superfeet^® FLEXmax™ insoles. An excellent introduction to doctor-recommended Superfeet shape, the special flex design hugs your feet and cradles your heels to help your footwear, and you, feel great. Durable 5mm thick Aerospring™ comfort foam delivers heel-to-toe comfort, while the flexible heel cradle provides structure and stability, reducing stress on feet, ankles and knees. FLEXmax insoles fit best in roomy athletic footwear.