Size(s): XS, Small, Medium, Large, XL, XXL The ASO with Plastic Stays ankle brace has the same great features as the original ASO ankle brace along with the addition of medial and lateral plastic stays to provide enhanced proprioceptive support. The removable plastic stays and padding on this ankle stabilizing orthosis have been upgraded to offer a lower profile and enhanced comfort. The ASO with Plastic Stays is bilateral and fits either the left or right foot. Features and Benefits: Plastic Stays: Enhance proprioceptive protection, especially during acute phase of ankle sprain treatment Stabilizing Straps: Angled stabilizing straps contour above the ankle for enhanced comfort and support. They form a complete figure-eight to help stabilize the ankle Elastic Cuff: Circumferential woven elastic cuff with rounded edges keeps laces and stabilizing straps secure. In addition, the cuff works in convert with the upper booth to help resist forces that may cause the ankle to roll CoolFlex Achilles Pad & Tongue: CoolFlex padding contains a latex free elastic fiber to provide superior comfort along the Achilles tendon and top of the foot. The shoe lace is attached to the tongue to ensure lace is always centered Invisible Seam: For improved comfort and durability, the seam is positioned along the rear portion of the boot Bilateral: Fits both the left and the right foot Indications: Inversion or eversion ankle sprains Medial or lateral ankle instability Subtalar joint instability Sizing: Use your shoe size as a guide only. For the best fit, measure your ankle circumference from the top of the ankle diagonally around the bottom of the heel. Ankle Circumference Men's Shoe Size Women's Shoe Size  XS 10 - 11in 6 - 7 5 - 6 Small 11 - 12in 7 1/2 - 9 6 1/2 - 8 Medium 12 - 13in 9 1/2 - 11 8 1/2 - 10 Large 13 - 14in 11 1/2 - 13 10 1/2 - 12 XL 14 - 15in 13 1/2 - 15 12 1/2 - 14 XXL 15 - 16in 15+