The Thermoskin Elastic Ankle is anatomically designed and will comfortably contour to the shape of your ankle. The Thermoskin Elastic Ankle has no seams. It provides even compression and support to weak and injured ankles, while minimizing bunching. Sizing Guide: Measure circumference around the ankle joint. Small 6 1/4 - 8 1/4 inches. Medium 8 1/4 - 10 1/4. Large 10 1/4 - 12 1/4. X-Large 12 1/4 - 14 1/4 inches. If in doubt on Thermoskin sizing it is generally best to select the larger size.