A UPS DIAD is a hand-held device that has been used by UPS drivers since 1991 when it was first introduced. The device tracks the package delivery from when the package is picked up for delivery to when it reaches its destination. It is also used to collect the digital signatures of recipients.
The device has undergone massive updates (it is currently in its fifth generation) over the years and has been instrumental in collecting data for streamlining the delivery process at UPS.