Keltner Channels using Typical Price and High Low Spread
Keltner Channels were introduced by Chester Keltner in his 1960 book How to Make Money in Commodities. They are similar to Bollinger Bands in that they consist of Upper and Lower bands at a certain distance from the Middle line.
Keltner's original definition was a 10 day SMA of the Typical Price for the Middle line with two times the 10 day SMA of the High-Low Spread applied to draw the Upper and Lower bands.
When the Close moves above the Upper band this could indicate that the stock is overbought although it could also indicate a continuation of a strong uptrend. When the Close moves below the Lower band this could indicate that the stock is oversold although it could also indicate a continuation of a strong downtrend.