Unique three-layer construction; first layer is Hydrolon terry which wicks moisture away from skin to keep you dry and comfortable. Perforated Hypolan blend middle layer is comfortable, cushioned and breathable, provides light compression which helps counteract tissue swelling. Durable nylon outer layer retains body's own heat, to naturally increase blood flow to damaged or painful joints and muscles to help encourage healing and pain relief. Open toe and heel for easy off and on. Hook/loop adjustable contoured compression. Fits either foot and easily inside a shoe. Affordable, long-wearing. Provides firm yet comfortable support. Lightweight, go anywhere support. Antimicrobial. Medium fits 9-10" (22.9-25.4 cm) knee circumference.