Customer Tally Counter

Allows you to keep a tally of people entering and leaving a building or anything else that needs to be counted.
Multiple devices can be used so that multiple entry / exit points can be monitored in real-time.
A maximum occupancy amount can be set that will warn when capacity has hit the maximum and not let additional people added. Full paid version purchased in the app allows unlimited maximum occupancy number.
Simple + and - buttons for adding and subtracting people.

Full Version also allows hiding of individual increment / decrement buttons, turning on and off sounds, and ability to prevent the app from going to sleep.

* Internet access is required.