If your piano is going to be placed on hardwood floors you may want to consider resting it on caster cups. Actually, if it's going to sit on carpet you may consider them as well. For hardwood floors the reasons are protection and style. Metal casters and hardwood floors don't work well together when the piano is rolled, or if the wood is soft, dents may occur even if the piano never moves. On carpet, small deep dents are the result of the piano sitting in one place for an extended period of time. Dents will still occur when caster cups are used but the dents will be shallow and you may be able to fluff or rake the carpet smooth. The only product that we sell are caster cups. They are designed and produced specifically for pianos. The three pictured below are the most popular style. The are 3.5" in diameter and have felt on the bottom. Most piano casters will fit within these cups. We can also order larger cups for pianos with bigger casters. Prices range from $15 to $25 per cup.