Thinkorswim/TD and the prophetalerts tab in ToS.
%R (WLR) is an oscillator. You can see em coming off bottoms if the move is strong, %R will flip to the upside and stay there.. then dips come in the form of, if you know which timeframe the oscillation will show up, you use it to look for areas of periodic weakness to play off pulls. Works on all timeframes, depending on the timeframe of your trade.
By definition it is a measure of closes. the percent of range.. tells you when a stock is breaking a range, in a range, etc etc
Market Data 
Markets 
AI
