The pick-up indicator is designed to notify express shippers using a drop box if the latest pick up has occurred. InControl personnel developed the electronics for this application.
This is a very challenging application, as operating temps range from -40F to +180F. Add in high impact (no one ever eases the door shut) and a long battery life is mandatory.
Currently, there are some 30,000+ of these installed across the USA - check for them on your local drop box.