Medium * Fits circum. 13.5 - 15 * Elastic Support for Prevention Treatment & Rehabilitation of the knee * Thermoskin elastics can expand contract and stretch and are made of a high-grade durable material that permits a full range of movement and are comfortable to wear during a range of activities * Anatomically designed with no seams this four-way stretch support combines Spandex with hosiery technology to provide protection and support for weak and injured knees