a knob, variously called gear knob, shift knob, gear shift knob or stick shift knob, forms the handle for the gear stick. typically the gear knob includes a diagram of the "shift pattern" of the gear selection system, i.e. the positions to which the gear stick should be moved when selecting a gear. in some older manual transmission vehicles, the knob may incorporate a switch to engage an overdrive; in some automatic transmission vehicles it may incorporate a switch to engage a special mode such as a sports mode or to disengage overdrive. both of the above-mentioned switches may also be found on the console or on steering column stalks instead. manual shifters on the steering column, if having only three forward speeds, are typically called a "three on the tree". the lowest of these gears, if set at a much lower ratio than a typical 1st-gear ratio, is often called a "granny gear".