The CCI is a trend-following system fpr commodities which produce cyclical price patterns. It was developed by Donald Lambert. It does not calculate length but is used as a timing tool.   The assumption is that prices move in channels for prolonged periods.  The market is oversold or overbought when the price moves too far away from the moving average value which represents the centre of the market. 

The CCI Index can be used as a breakout system: Go long over the +100 line or go short below the -100 line.  All positions are liquidated between the two lines.