This 3” garage door pulley is designed for use with residential extension spring systems and helps guide the lift cable smoothly during door operation. Each pulley features a 3/8” bore and is rated for up to 100 lbs. at 10,000 cycles on an 8’ garage door. A practical replacement for worn or damaged pulleys in standard extension spring setups. Sold as a pack of 3. Fasteners are sold separately.