Made of ABS. This key tracker both supports ios and android systems. Suitable for almost all smartphones. If you are in need to keep track of something important such as keys or bags, a Bluetooth tracker is a perfect gadget to solve this problem. Download the app to your smartphone and connect it to the tag. Attach these trackers to your wallet, bags or any items valuable, you can track your item everywhere with the app, it will even show you the location on a map. On the other hand, simply tap the button twice on the tracker and your phone will ring to reveal its location. Replaceable batteries.