Size medium black over the calf combat boot sock by Thorlo (MCB). Fits men's shoe sizes 5 1/2 to 8 1/2 and women's shoe sizes 6 1/2 to 10. Engineered especially for military and tactical boots. Heavyweight padding at the ball, heel, and toe protects the foot in demanding field conditions. Spandex holds top up, prevents it from creeping down and bunching up. Made of 94% thor-lon acrylic, 13% stretch nylon, and 3% spandex. This item is worn by both senior members and cadets of the Civil Air Patrol (CAP) with BDU's, flight suits, and utility uniforms.