I think the height of this is the iPhone's home button (which is gone in iPhone X, but regardless).
It has 6 functions, on a single button, based on how light or quickly you press it - single click, long press, double click, single tap (lighter then a click), double tap, triple click (if enabled)
It has 6 functions, on a single button, based on how light or quickly you press it - single click, long press, double click, single tap (lighter then a click), double tap, triple click (if enabled)