hese caster cups are the premier line of protection for your customer's flooring and carpeting. Over a period of time, due to the piano's 400 lb. to 1,200 lb. weight, holes will develop in the floor or carpet, making the caster cup a very necessary piano accessory. These caster cups measure 5" outer diameter, 2-1/2" inner diameter and have a felt pad glued to the bottom to protect floor finishes. Made from selected hardwood.