Current Position Information
The number of bars since this position was entered, not counting the entry bar.
This can also be though of as "nights held". On entry date, BarsHeld=0.
For example, if you entered on a Monday and want to exit Friday, your ExitRule formula would be BarsHeld=4 (assuming there were no holidays that week). You are exiting the 4th trading day after your entry day.
See Specifying a Time Stop for more information about this topic.