ITEM NAME:Round Electronic Keyboard Piano Caster Cup Instrument Parts Anti Slip Desk Features: Made of ABS material, heavy duty and durable to use. Aim to be placed under a piano legs in order to protect wood, tile, and carpet from piano caster damage. The piano caster cups are designed specifically with a low profile of to keep the piano's pedals at the right height. Underside of each caster cup have sound-proof antiskid effect. Connect tightly with piano caster, making the body of the piano is not easy to be shooked. Specifications: Item type: piano caster cups Material: ABS Color: black Size: about 8.7 x 2.1cm Package includes: 4pcs x piano caster cups Notes: Transition: 1cm=10mm=0.39inch 1. Due to the different monitor and light effect, the actual color of the item might be slightly different from the color showed on the pictures. Thank you! 2. Please allow 1-3cm measuring deviation due to manual measurement..Connect tightly with piano caster, making the body of the piano is not easy to be shooked. Underside of each caster cup have sound-proof antiskid effect. Anyway we will try our best to avoid this kind of thing.