Tells Me: The price is relatively far from its 20-bar average price. The Commodity Channel Index (CCI) measures the deviation of the price from its average value (comparing to a chosen moving average, typically 20 bars). The oscillator is normalized by dividing by the typical deviation, so we get an oscillator fluctuating roughly between +100 and -100. Many traders use these as overbought (+100)/oversold(-100) markers and watch for signs of reversal, but original use was to consider long positions when CCI is above +100 (bullish event), and short when below -100 (bearish event). When the price crosses back in between +100 and -100, another event is triggered to indicate an end to the prior bullish or bearish situation and a possible opportunity to close out such a position.