The polyurethane skin on the kneeling surfaces of these pads prevent build-up of sharp items such as splinters that can scratch floors. The polyurethane is also resistant to tearing and penetration, providing extra durability. Comfort Knees are designed for floor installation. They provide protection for both kneeling or knee kicking, and can stay on at all times. The extra wide straps won't pinch your legs. The contour conforms to the motion of your knee. Made from flexible yet durable neoprene material, these pads are machine-washable. Inner knee pad is replaceable. Net weight: 1 lb./set.