The highs and lows of the current day, week, month or year can often be significant levels for trading. These are places where stop loss orders tend to accumulate, and the levels can be targets for stop-runs, reversals, and key levels for break-outs. They can also often act as support and resistance.
There is no one strategy that works in all cases, but something significant usually happens at these levels, and so it is clearly useful to have them marked on your charts, as key reference levels.
The indicator can show the high/low levels for current day, week, month, year and 52-week periods. Of course, colours and line widths are customizable.
The indicator is available from my blog. See here for more information.