Set of 4 rubber circular pads, ideal for soundproofing and vibration absorption. Thank you for viewing. I am selling items that are no longer needed due to the disposal of a piano I owned. - Quantity: Set of 4 - Material: Rubber - Design: Circular non-slip surface - Application: Soundproofing and vibration absorption - Color: Black - The deep caster receivers prevent wheel detachment and slippage. - Effectively suppresses vibrations transmitted from the piano's casters to the floor, reducing vibration noise transmitted to the floor below. - Improves sound quality by suppressing unwanted resonance. I used these at my parents' house when they had a piano, placing them on the tatami mats that came with the piano. There were no dents in the tatami mats. ⚫︎ There are small scratches and scuffs, but there is no problem with the product quality, and they are in a condition that can be used without any issues. I hope that those who understand that there is some wear and tear will purchase them.