Bluetooth Low Energy Explained
 

Bluetooth’s power-hungry nature has made it impractical for many types of wireless devices in the past. Bluetooth Low Energy is changing this, enabling new types of devices that can operate for months or years with small batteries.

For example, you’ll be able to put a cheap, small device on your keychain so you can track the location of your keys from your phone. The device’s battery will last an entire year without any recharging necessary.

http://www.howtogeek.com/176437/blue...-now-possible/