Bollinger Bands illustrate the dispersion of prices around the average. Bollinger Bands are composed of an upper and a lower band. Usually, the price oscillates between these two bands. When volatility increases, these bands move apart as they contract during a phase of low volatility. In terms of technical analysis, we can read the graph as follows: if the price is close to one of these bands, we are far from the average and it is likely that we are overbought or oversold. In other words, it is likely that the trend will change direction in the short term.