Compatible with Schwinn Models: 790p, 800p, 810p, 820, 835p, 845p, 860p 1600.2 2600.1, 2600.2, 3600.2, 4600.2, 5120.2, 5450.1, 5450.3, 6100.1, 6100.2, 6300.1, 6310P, 6500.1, 6700.1, and MANY MORE. STILL NOT SURE? Measure your treadmill key insert hole, if its 1'4" in diameter (or slightly more), this is the correct key for your schwinn treadmill