The pad is held in place by a circumferential, stretchable, soft acrylic terry loop material inside with a flat knit on the outside. The foam pad is bar-tacked to the material at two points to prevent slippage, yet allows the person to move the joint without a shearing effect on the skin. Foam Pad model features an air-cushioned, polyurethane foam pad with a tricot lining. Gel Pad model provides additional protection to insulate against shock and vibration. Protects against abrasion and promotes healing of pressure ulcers. Excellent conformity around bony prominences. Machine or hand wash. Air dry. Sold in pairs. To size, measure circumference at ankle or elbow crease. If in between sizes, choose larger size. Latex free.