Bollinger Bands are a technical indicator created by John Bollinger, being used to measure market volatility.

When the volatility is low (small number of trades) the bands contract and when the volatility is high, they expand.

Rejection from Bollinger Bands

As a rule, the price tends to reject from a Bollinger band, reaching the middle of the area between them.

The reason of rejection is that Bollinger bands serve as dynamic supports and resistances.

The longer the period they take into consideration the stronger the support / resistance will be.

Bollinger bands are useful when the price moves without describing a trend.

Here's how they work during a trend.



Bollinger Squeeze 

Bollinger Squeeze occurs during a trend when the bands are approaching each other, signaling an imminent breakout.
If a candle closes over the upper band, as a rule, the price will continue to rise, and vice versa, when a candle closes under the lower band, the price will continue to fall.
 

Thus, Bollinger Bands allow us to capitalize on market situations from their very beginning.

Such situations could allow us to short-term trade opportunities, on average two to three times a week.