Who knows what this is and what the USPS used it for?

I bet there are a lot of you who have never seen one of these..  I used one when I first came to work for the USPS..   So who can tell me what it is and what it was for?  I will share the answer after I see if anyone knows!!

This is a collection wand. There were little disc buttons placed inside blue collection boxes. You would hold the wand on the button until it beeped. Then it would be downloaded and would show the time the collection scan was performed.