This indicator shows a "resistance" encountered by the price in relation with volumes. If a bar is big, the price encountered much resistance to plot the bar, if it's small the price encountered low resistance. This informations help taking better decisions based on VSA ( Volume Spread Analysis), making the spread between bar volume and bar extension clearer to read. If you see some very large bars and all the others quite small try to use the "threshold" param, especially on lower timeframes. On indexes (nasdaq, dax , dow jones) I found that setting threshold to 5 is good for M1 too, but feel free to try other values to find the right one for you. Feedbacks are more than welcomed!