
Relative Strength Index (RSI) is an oscillator that follows prices and ranges between 0 and 100.
RSI can help traders to predict price movements in the decent time period. First the 14-day RSI was introduced, and no 9-day and 25-day RSIs became widely popular.
It is a popular indicator indeed. Also it's rather simple to calculate it and to use it due to its straight-forwardness. When I was trading I used it sometimed, and got what I needed. By the way, my forex broker was AvaFX, but unlike those people who believe or spread the rumors that AvaFX scam, I'd like to disappoint you and tell you that it isn't so.