These Hard Wood Piano Caster Cups are designed by CPS Imports to be placed under a piano's legs in order to protect floors and carpets. Caster cups are critical in the protection of hardwood floors, carpets, tile, and other flooring materials. It has felt on the bottom. Made of solid hardwood. Dimensions: 3 1/2" - outside diameter, 2" - inside diameter. Available in walnut color. Listing is for 4 caster cups.