The Alpha Medical Plastic Shell High-Top Air Walker provides comfortable stability for acute ankle sprains, stable fractures of the ankle and soft tissue and stress fractures to the lower leg with the addition of a pneumatic air bladder system that inflates around the ankle, providing customized compression. The Velcro adjustments, skid resistant sole and completely open-able liner allow for easy application and adjustments. The closed toe provides extra protection to the toes. Size Guide: Small: Men’s Shoe Size 5 – 7 / Women’s Shoe Size 6 – 8 Medium: Men’s Shoe Size 8 – 11 / Women’s Shoe Size 9 – 12 Large: Men’s Shoe Size 11 – 12.5 / Women’s Shoe Size 12 – 13.5 X-Large: Men’s Shoe Size 13 and up / Women’s Shoe Size 14 an up