The Parma BB Indicator is an incredibly useful and popular free Forex indicator for MT4. The indicator works by tracking and displaying the current price levels of a currency pair in relation to the upper and lower Bollinger Bands. When the price is close to the upper band, the indicator will show a buy signal, and when the price is close to the lower band, it will show a sell signal. With the Parma BB Indicator, traders can easily identify profitable trading opportunities and make better trading decisions.