These filters compare the price of the last print to the high and the low for the previous trading day.  0 means that the last print was at the same price as the previous low.  100 means that the price of the last price was the same as the previous day’s high.  50 means that the last price was exactly in the middle of the previous day’s trading range.  This number can be below 0 or above 100 when the last print is below the previous day’s low or above the previous day’s high.