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 isn't available. Comes with a CR123 battery.