Treadmill safety key: magnetic work, can work easy and quick on most treadmills. Strong clip can easily clamp to any part of your clothing and it's strong to hold. Fit to a wide variety brands of treadmill which requiring a round magnetic switch safety key. It can protect you effectively when you using treadmill. Item Name: Treadmill Safety Key Material: Plastic + Magnet Total Length: 1m/39.37" (Approx.) Diameter of Magnet Shell: 2.8cm/1.10" (Approx.) Diameter of Magnet: 1.5cm/0.59" (Approx.) Clip Length: 5.8cm/2.28" (Approx.) Clip Width: 2.7cm/1.06" (Approx.) Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x Treadmill Safety Key