SIZE SMALL: Men's Shoe Size 4 1/2 - 7, Female Shoe Size 6 - 8. The Superior Braces Low Top, Low Profile Air Pump CAM Medical Orthopedic Walker Boot for Ankle & Foot Injuries is a top of the line pneumatic (air pump and liner bladder) protective boot. This CAM walker allows you to adjust the level of desired compression with ease. Features an inflatable liner with easy release technology and quick release, and easy to manage fastening straps. The Low Profile CAM Walker is a top option for people suffering with soft tissue injuries, grade 2 and 3 sprains, stable fractures and patients that are in need of post-operative stabilization. The Superior Braces Low Top, Low Profile Air Pump CAM Medical Orthopedic Walker Boot for Ankle & Foot Injuries will help to reduce pain, swelling and edema of foot and ankle, without costing a small fortune. SB Low Top Air Fracture Boot Size Chart XSmall: Men's Shoe Size Up To 4, Female Shoe Size Up To 5 1/2 Small: Men's Shoe Size 4 1/2 - 7, Female Shoe Size 6 - 8 Medium: Men's Shoe Size 7 1/2 - 10, Female Shoe Size 8 1/2 - 11 1/2 Large: Men's Shoe Size 10 1/2 - 12, Female Shoe Size 11 1/2 - 13 1/2 XLarge: Men's Shoe Size 12 1/2+, Female Shoe Size 13 1/2+