Plots the NYSE, NASDAQ, AMEX UP Volume and DOWN Volume ratios as a histogram - and adds the index UVOL / DVOL ratios as a line graph.
DVOL is represented as negative - UVOL as positive. When either is above 2 its a good predictor of the day's outcome. At least - it tells you if the bulls or bears are winning the day.
Really simple to use / edit to your needs