As there has recently been some discussion on the Yale changeable deposit box locks.
Here is my example, which is an original factory cut-a-way sample lock from the Yale bank lock factory.
Here some of the keys that would have been supplied are shown, they are from left to right :
1 - The managers key, which is required to change the combination of the lock.
2 - The custodian key, which is required to allow the renters key to function.
3 - The renters key which ultimately opens the lock.
Here is a poor image of the catalogue page describing these locks.
