Performance Timer is a free iPhone app developed by Andrew Schweig. It falls under the category of Utilities & Tools and is designed to be a large-display countdown timer.

The main purpose of Performance Timer is to monitor the time remaining in a performance, presentation, or any other time-sensitive event. The app does not sound an alarm when the time runs out; instead, it visually indicates the end of the set time by turning the numbers red. Additionally, the timer starts counting up after reaching zero, allowing users to see how long they have gone over their target time.

With Performance Timer, users have the flexibility to set the time from 1 to 99 minutes, accommodating a wide range of time requirements. The large display ensures that the timer is easily visible, even from a distance.

Overall, Performance Timer is a useful tool for anyone who needs to keep track of time during performances or presentations. Its simple yet effective design makes it easy to use and provides a clear visual indication of the time remaining.