Bollinger Bands
Volatility bands plotted a number of standard deviations above and below a moving average, widening and narrowing as volatility changes.
Bollinger Bands wrap a moving average with an upper and lower band set a fixed number of standard deviations away (commonly two). The bands expand in volatile markets and contract in quiet ones; price touching a band can signal stretched conditions.
endeavr.ai includes Bollinger band position and bandwidth among its engineered volatility features.