The master lock 5404e single key safe holds a single key which is permanently affixed to the storage compartments removable cartridge to prevent misplacing the key after use strong sturdy wall mount design for permanent installation set your own 4 digit combination with hundreds of code variations for keyless convenience and is sized to fit easily between storm door and entry door or other small spaces it has a plastic cover which protects the combination dials from weather dirt and grime and an