These CPS 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. Dimensions: 5 1/2" - outside diameter, 2 1/4" - inside diameter. Available in ebony color. Listing is for 3 caster cups.