The SMI Forex Indicator is a useful and popular free MT4 indicator, providing traders with a simple yet effective way to identify potential trading opportunities in the Forex market. The SMI indicator uses two moving averages, a fast and slow one, to generate buy and sell signals. When the fast moving average crosses above the slow moving average, it is a buy signal, and when the fast moving average crosses below the slow moving average, it is a sell signal. The SMI indicator is a great tool for traders looking to identify potential trading opportunities in the Forex market.