Grade F1 Pressed Wool Felt Disc, White, Meets SAE J314, 3/8" Thickness, 4" Diameter, Adhesive Backed

These full wool discs are used to place the caster cups on, and then you place the piano wheels in the cups. When placed on a full wool rug, the combination is very effective in absorbing excess sounds and vibrations from a powerful acoustic piano. To me, an excellent product for those living in a building with shared walls in order to avoid neighbor conflicts over sound traveling. Thanks.