For the WFM700 audio monitor+ what is the small bar on top of the level meter bars?

For the WFM700 audio monitor+ what is the small bar on top of the level meter bars?

The small bar is the peak hold indicator. From the configure menu, you can set the time to hold the peaks, and you can turn this indicator off if desired by pressing the configure button, select AUDIO DISPLAYS, select PEAK HOLD display then select off.