Gatekeeper Key is a small device, more or less a key-chain, is exactly that. However, thanks to Bluetooth technology, it has the ability to lock and unlock your computer (Windows and Mac OS) based on proximity. It also acts as a locator and can pair to your smartphone (Android/iOS) to give you a location based alert, for example if you lose your keys.
Gatekeeper key help to protect your privacy as it automatically lock & unlock your computer
More info :-http://www.gkchain.com/