Donchian channel
The Donchian channel was invented by a trader called Richard Donchian. The two bands of   the channel are based on the highest high and the   lowest low of a set period. Donchian himself based   both channel bands on the highest high and the lowest low of the last 20 days.   Donchian would consider opening a long position when the market price goes above   the 20-day channel. Alternatively, he would consider opening a short sell   position when the market price goes below the 20-day channel.
            
            Another   trader, Curtis Faith, who worked on the Turtle Trading system, uses fairly similar values for the   two bands. In the case of Faith he opens a position when the market price   crosses a 20-day channel. He then, however, uses a 10-day channel as his stop.   The Donchian channel is also used by German trader Birger Schäfermeier for closing   positions.
            
            This example shows a Donchian   channel with both bands based on 20-day periods.

This example is the same chart as above. It shows, however, a Donchian channel with the upper band based on a 20-day period and the lower band based on a 10-day period. Some traders would open a long position (if the underlying trend is bullish) when the market crosses above the upper band and they would use the lower 10-day band as stop.
