This is the time-of-day companion to uchasArTimerStopDate, specifying exactly when on the stop date the timer's active window closes, and it's subject to the same trap the MIB documents for the stop date: if the combined stop date/time is already in the past relative to the system clock, the timer simply never activates. An admin setting up a timer intended to run through the end of a business day would pair a specific stop time like 18:00:00 with the stop date to ensure the schedule closes precisely then rather than at the 00:00:00 default. For example, an admin wanting nightly firings only between 10 PM and 6 AM would set stop time to 06:00:00 paired with the appropriate stop date, ensuring the window closes at dawn.