The master lock 540 wall mounted key lock box enables the safe storage of house keys or even cash door keys can be safely left for children to get in after school for an elderly family member you need to visit on a regular basis or for just storing keys safely the 5401 is packed with high quality features and it is fitted with an easy to set 4 digit combination security lock with hundreds of multiple code options a tough metal body provides the ability to store larger items and not just keys can