1ABS Material: This magnet treadmill key is made of premium ABS. Strong magnetic working, sturdy and not easily damaged, suitable for long term use by runners. 2Strong Clip: This safety switch can easily clamp to any part of your clothing and it's strong to hold. Easily clips to virtually all types of clothing, easy and convenient to use. 3 Replacement: This universal treadmill safety key is suitable for most of running machines, is a treadmill key replacement for you that you can enjoy your exercise. 4A Must Have Accessory: This magnet safety key is compact and lightweight, easy to install, extremely important for maintaining the efficient operation of any treadmill exercise. 5Usage: This lock is an automatic protection device of the treadmill. When the safety switch is out of the sensing area of the treadmill, the treadmill will stop working immediately and give a prompt tone, so as to protect the user from falling down and getting injured during exercise.