If you have lost your treadmill safety key or you simply want to purchase treadmill spare parts, you can buy one directly from LifeSpan. The thin prong replacement safety key works with the following LifeSpan products: TR1200i Treadmill (2019 Model and later) TR2000i Treadmill TR3000i Treadmill (2016 Model and later) TR4000i Treadmill (2016 Model and later) TR5500i Treadmill TR2000e Treadmill TR3000e Treadmill TR100 Treadmill TR200 Treadmill TR800 Treadmill LS-5T Treadmill TR1000-SL Treadmill TR1000 HRC Treadmill TR1500 Treadmill