Donald Lambert's indicator divides the gap between the typical price and its average by a fraction of the mean absolute deviation, so readings of plus or minus 100 correspond to a meaningful stretch. It is unbounded, so extreme trends can push it to 300 or beyond.
That unboundedness is its distinguishing feature. Unlike rsi or stochastics it cannot saturate, so a very strong move keeps registering as very strong rather than pinning at 100.
It is used both as a mean-reversion tool, fading extremes, and as a breakout tool, entering when it crosses above 100. Those are opposite strategies from the same number, which should be a warning about how much interpretation the indicator requires rather than a sign of versatility.
Related: oscillator, mean-reversion, rsi, momentum-indicator, awesome-oscillator