Excellent setup for the tall, heavy pre-depression upright pianos and studio pianos. WILL NOT FIT SPINET OR CONSOLE PIANOS! These casters are 2" diameter wheels and are double wheel casters - they will be wider and slightly taller than originals and will require some work to install properly if they are larger than your original casters. Rated for 160 pounds each caster. Rubber wheels are easier on most floors and won't leave rust stains on carpet. Kit includes bushings for the socket stems (in case existing hole in piano is larger than the 1/2" new stem - very important to prevent breaking socket). 4 of each of 4 thicknesses of Ragland's exclusive ProFit Shims are also included in the event they are needed to level the piano or reduce the depth at which the caster socket sits in the caster recess in the body of the piano.. Screws are #10 size, 1-3/4" long -allows use of the included shims while providing enough length to secure the socket. Original screws are often bent, missing or rusty. Halfway through the job is NOT the time to find out you need any of these parts! If you have questions regarding proper casters for your piano, please feel free to contact me.