Piano Caster Cups ,Very Strong ABS Furniture Cups ,Fits All Wheels Furniture, Floor Protector Bed. Non-Slip & Anti-Noise Foam (PA-15) Designed for use with grand pianos Protects wood, tile, and carpet from piano caster damage Designed to be placed under a piano's legs in order to protect floors and carpets Made for High-Quality Plastic Underside of each cup is lined with felt pad