1 (also labelled "L"): Restricts the transmission to 1st equipment only, often called a "small equipment". This is useful when a big torque is required on the wheels (such as, when accelerating up a steep incline); even so use at bigger speeds can operate the motor at an abnormal velocity, https://gearboxauto42963.blogoscience.com/40423772/the-ultimate-guide-to-gearbox-auto