This big padlock form has been for decades, but in this era of smart things, someone give it with bluetooth and smart chip. This kind of change as a result, you never need the key, as long as have a cell phone can unlock. And, this way is more easy to share -- — Who don't have the key to, as long as the phone on a share, your friends can also open the lock. It will track all activities, such as lock, unlock, warned that there are logging.