Unique shape allows the heel to float in an air cavity with absolutely no contact. Features include: an integrated toe post; open design to prevent heat and moisture build-up; soft fabric that wicks moisture to reduce friction and shear; super soft laminated foam material for increased comfort and cushioning; extra comfort padding at sensitive Achilles area; resilient plastic base to maintain a neutral foot position; adjustable straps to accommodate edema (swelling) changes; cover is one complete piece for easy application. Small/Medium fits shoe sizes Women's 5-10, Men's 4-9; Large/X-Large fits Women's over 10, Men's 10-13.