A while back I remember getting a call from a customer who has a small store in the area and wanted to upgrade the lock system on the back door of the store to a key-less entry lock system. Luckily, I just got an order of few key-less entry locks, so I had various options for him to choose from. He mentioned that it's a small store and he probably have around 10 employees working shifts, so I knew he won't have a need for a lock that had large multi-user capabilities.
When I arrived to the store, the owner showed me the door where he wanted the lock to be installed. It seemed that the best solution for what he wanted and the type of door he had there was a Simplex type key-less entry lock. After agreeing on the option, I started the installation which didn't take very long. I then helped the customer program the lock for the number of users and codes to access.
Reno locksmith co-worker of mine to consult and he gave me the idea of incorporating a padlock that would eliminate the use of the Simplex handle one locked.