This indicator shows where the candlestick close occurs. The range of the indicator is from 0% - 100% (0% at the bottom, 100% at the top). If a bullish candle closes at the highest price it reaches within its allotted time period then the indicator will show 100%. The opposite is true for a bearish candle closing at the lowest price of it's allotted time period, the indicator will show 0%. If the candle closes directly in the middle of the entire range of the candle (from high to low) the indicator will show 50%.
This can be used as a good tool to indicate the direction of trend or a reversal about to occur. The two horizontal lines on the indicator are set at 20% and 80% by default. If candles close above 80% this indicates a strong bullish trend. If candles close below 20% this indicates a strong bearish trend.