Similar to SuperTrend or the ATR trailing stop lines that are common-place in chart indicator circles, the B3 High-Low Trail-Trader works as a back-break line to flip binary long and short biasing. Here is the strategy set to 7 bars back. You can find this style of trading system in several books, and there are many ways to come to the trailing stop line, so I imagine the bars back length can be slid around to suit certain charts. This happens to be my favorite trailing line.