SPY weekly with 15,2 Bollinger Bands 21,2 Bollinger Bands 26,2 Bollinger Bands -- 6 months of price action https://c.stockcharts.com/c-sc/sc?s=SPY&p=W&yr=2&mn=11&dy=20&i=p28118575194&a=700308111&r=1579493514109