Don’t have an iPhone? Don’t sweat it.
With Keycard you can pair a whole smorgasbord of devices. Got an iPad or iPod touch? Any Bluetooth® enabled device can act as a "keycard" to your precious Mac.
Incase of emergencies...
Not that you'll ever have one, but just in case. Keycard is built for you to be able to have your own custom 4-digit pin as a fail safe. Say you don't have your device on you or maybe it's dead, lost, or stolen. Good thing we thought about that, right?