Image Sources: Instaforex.
It is a price Channel and developed by Richard Donchaian. It is a trend following indicator and almost similar to Bollinger Bands. In addition, it took it takes the help of high and lows of price in the calculation.
Usage in simple words is Buy when the price clossed above the 20 channel and Sell when the price clossed bellow the 20 channel.
Ref: instaforex.