The Master Lock Select Access SMART™ Bluetooth Large Key Box can be used inside or out It is unlocked via a Bluetooth® connection using a smartphone or tablet Download the free app from the Apple Store or Google play This lets you share access with others one time or permanently Keeps a record of all the access history and has a low battery reminder for peace of mind There is also a backup numeric keypad for access if a bluetooth connection isnt available Comes with a CR123 battery