This pair of 30 In. x 10 In. concrete sliders is made from tough, heavy-duty ABS plastic. The knee boards has rounded edges to prevent digging into concrete. The plastic resists corrosion from use and makes the boards easy to use and the plastic makes them easy to clean. The white material can be used with white and colored concrete with confidence. Toe bracket secures the foot and allows for an ease of back and forth movement along the work surface. Each board features an adjustable kneepad to provide comfort on your knees as you move around the cement. Knee pads are made of durable, lightweight polyurethane with two adjustable web straps to hold pads to knees. Each pad is molded in one piece to eliminate seams that can lead to chafing and discomfort. Remove the knee pads and use them on their own for additional versatility. The kneepads are replaceable to extend the life of the sliders. Use Kraft Tool Co. Polyurethane Knee Pads (#WL080) as replacements. Kraft Tool Co.® has been an American manufacturer of quality hand tools for the concrete, masonry, asphalt, plaster, drywall, tile, floor covering, and leveling trades since 1981.