WOGOD (PA-11)Solid wood Upright Piano Caster Cups .(1 Set of 4 Black) Package: 1 box (include 4pcs piano cups) Material :SOLID HARD WOOD Protects metal and brass wheels from rust or tarnish Underside of Each Cup is Lined With Felt Pad, Have Sound-Proof -Antiskid- Vibration free chassis Effect Very elegant design enhances piano and room beauty providing a real classy look