Noke

This is the world's first Bluetooth padlock,it requires just your smartphone with a Bluetooth connection and the noke app from a smartphone’s respective store.

How To Use
Download the noke app from the app store and the noke padlock automatically finds and pair with your phone
To unlock noke, you press the shackle on the padlock and then it finds the phone it has been paired with and then it unlocks.
It also has a contingency plan for when you loose you smartphone.

P.S ; Also check the product on indiegogo

PRICE
$40