QUIET: Nylon Wheel reduces garage door noise by at least 75% compared to standard steel rollers DURABLE: 6200Z Bearing rated 15x standard roller for 130,000 door open and close cycles at 150 lb. load providing maximum durability EXTRA LUBRICATION: lubrication groove on roller to disperse lubrication over extended period STANDARD REPLACEMENT SIZE: 1-13/16" diameter, 4-5/8" long shaft