The ball drive, or planetary reduction drive, allows the user to obtain finer tuning control with silky-smooth reduction, so that the driven bore rotates one time for every 25 rotations of the fine input knob and one time for every 5 rotations of the coarse input knob.
FINE RATIO: 25:1, Reduction
COARSE RATIO: 5:1, Reduction
Constant input/output relative position?: NO