Volatility indicators frequently employ ranges to depict the underlying price behaviour and volume of any fluctuations. This is useful because any significant change in behaviour could provide an excellent entry signal. Common examples include Bollinger Bands, ATR, and Envelopes.
So traders have four types of technical indicators at their disposal. It is entirely up to them which ones they use, but it is usually recommended that they have at least one of each to provide additional proof for initiating a trade.
Technical analysis in forex trading is all about probabilities. When traders initiate a long position, for example, they want all of their selected signals to be signalling an upward movement, implying a high likelihood of an upward movement occurring. This high probability trading approach should produce more winners than losers over time if they use a strict stop loss strategy and these various types of indicators to confirm positions.