Instruct: Classify a given Amazon review into positive or negative sentiment.
Query: Used under a piano

I bought these castor cups to use under an upright piano on a new wood floor. My main concern was dispersing the weight of the piano so that the metal castors would not dent the wood. This product seems to do the job.In hindsight, however, I probably would have bought the bigger ones to disperse the weigth further.