Bollinger Bands can be applied in all the financial markets including equities, forex, commodities, and futures. Bollinger Bands can be used in most time frames, from very short-term periods, to hourly, daily, weekly or monthly.
Bollinger Bands are a technical analysis tool, specifically they are a type of trading band or envelope. Trading bands and envelopes serve the same purpose, they provide relative definitions of high and low that can be used to create rigorous trading approaches, in pattern recognition, and for much more