Different lengths produce short-term and long-term indicators that can help with finding the trend and impulses within the trend.
It can also find reversal points when all 4 are at the extreme at the same time. Ex. All 4 Stoch are above 90 or under 10 !! This could signal a bottom or top is soon to happen. (This is not always true as it depends on many factors.)
Many visual options make it even more customizable. Fill between Stoch, background colors, Crosses.
Divergences are not always accurate, depending on settings and timeframe, but they can be useful in certain situations.
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In closing, no indicator can give perfect signals, you need to use them in conjunction with other information to make better decisions. I hope you like my indicators and that they help your trading.