Motorola Keylink accessory helps you find your lost phone20
We have to hand it to those chaps at Motorola. They have designed Motorola Keylink to work on both iOS (7.1 or higher) and Android (4.3 or higher) handsets. The Motorola Connect app is available from both the Google Play Store and the Apple App Store. Those sporting the Motorola Moto X, Motorola DROID Turbo, or a phone running Android 5.0, can use the trusted device setting to keep their phone unlocked as long as they are in the range of the Keylink. By the way, the accessory is protected against splashes as Motorola says that it can get "a little wet."
The Motorola Keylink is priced at $24.99 and is available from Motorola.com, or from T-Mobile. The battery lasts a year, and can easily be replaced. We should also point out that if you are always losing your keys, you can also use the Keylink to find them. If you are using the Keylink as a key ring, finding your missing keys is a snap. When the keys go missing, open up the Motorola Connect app from your phone to view a map that will lead you right to them.
source: Motorola (1), (2) via AndroidCentral