Pro-Tec Athletics 3D Flat Premium Ankle Support Benefits of 3D Flat Stitching Technology Flat Knit an advanced horizontal knitting technique, allows for customized stitching to achieve 3D shaping of the fabric, providing optimum fit. Contours to your ankle area, providing optimum support. Medical Application: Recommended use for minor to moderate ankle sprains and strains. Design Theory: Breathable, multi-directional stretch allows full range of motion while maintaining high level support. Sold As Each Measurement based on shoe size Narrow feet/ankles fit one size smaller