The Bollinger Band is a technical analysis toolbox around a set of lines plotted two standard deviations away from a simple moving average (SMA). Please refer to this article for a complete explanation of this tool.
This is a conditional block based on the %B indicator. This block allows you to trigger the sequence of actions of your flow according to the values of this indicator.
Analysis period: The period that BOLL will take into account (If you choose 4H, BOLL will use 4H candles).
Trigger type: Position or Crossover
— Position: Triggered when signal is above or below the analyzed band
— Crossover: Triggered when signal cross the analyzed band (middle, top or low)
Signal type: Define the type of signal to be analyzed, below or above selected band.
Analyzed Band: Select the type of band you want to analyze, the middle band (SMA), one of the 2 deviations band upper or lower.
Percentage: Minimum percentage to validate the Position, Crossover trigger.
In the above image we can see that the BOLL block is triggered when the price goes under the lower BAND.
Because the signal type is Below, the trigger is Position (it could have worked with Crossover as well in this case) and we are analyzing the Lower Band, other bands are not analyzed in this example.
This Block can be really efficient combined with other block like MAs, more on Moving Average here.