One (also labelled "L"): Restricts the transmission to 1st gear only, often called a "low gear". This is beneficial when a significant torque is required with the wheels (for example, when accelerating up a steep incline); even so use at bigger speeds can operate the engine at an abnormal speed, https://gregorywiorr.dgbloggers.com/34591555/the-5-second-trick-for-gearbox-auto