369656 1. Moisture-proof. 2. Protect the floor from scraches and traces made by pressure of piano. 3. Make the piano confirmed， do not slide due to esternal influence. 4. Avoid the contact between wheels and ground. It is not easy to get rusty. Adaptable to: Upright piano ( Vertical piano) Material: Solid wood Color: Black Size: Diameter of base 10cm; Diameter of groove 4.2cm 4 X Caster Cups Carton Packaging