This is a very simple but quite powerful indicator which looks at the RSI simultaneously over the 4h, Daily and Weekly timeframes, and places bands on the chart when one or more timeframes move into oversold/overbought territory. For further filtering I use the 200 day SMA to determine if we are in a Bull or Bear market, which puts a bias on the RSI (30/80 in a Bull market and 20/70 in a Bear market).
The deeper the colour, the more oversold the market is. The weekly RSI can be used as an early warning sign, with the Daily/ 4h RSI useful to identify local peaks.