They are a follow-up indicator indicate simply the movement of a mercadol, with a top band or ceiling and a lower band soil. This indicator is composed of a simple moving average and the two bands already mentioned, which are statistical points to identify the largest movement within an average value. The Bollinger bands can resemble a channel guide which will be identifying the movements of currencies at a market price.It must be used simultaneously with other indicators generally is calculated through a simple 20-day moving average, without that this indicates that not be more or less days as a point of reference for the indicator. If they used less than 20 days in the calculation are said to be short-term bands, which are more sensitive to the movement of the prices of currencies; on the other hand if the calculation uses an average mobile upper to 20 days, says that gangs are long term and their behavior will be more conservative is important to note that you bands do not they indicate points of entry or exit. They are only a guide or channel inside of which is expected to move prices. Hence important to stress the fact that this indicator shows us that a market is with prices moving between two values specific and it will be decision of the inverter if it enters downward when the price is on the ceiling of the band or if it enters upward when the price is on the floor of the band. It is good to also highlight that in a volatile market, with prices moving with strength or speed within two points, bollinger bands tend to swell and become shorter if there is little movement or price fluctuations are slow. Finally this indicator can be very useful in markets side, since they can point out more clearly the ceilings and floors of the price of a currency.