Bollinger Bands are a technical analysis tool made up of a moving average and two bands placed above and below it at a set standard deviation. The bands expand and contract with volatility. When the price touches or breaks the upper band, the asset may be overbought; when it hits the lower band, it may be oversold.
Example:
If Ethereum repeatedly touches the lower Bollinger Band while RSI is low, a trader might see that as a potential reversal setup for a long entry.