Scale Dials are a removable device with a face that is marked in predefined units to indicate the degree that a shaft has been turned. The knobs have a shaft size of 0.125” (3.18 mm), 0.236” (6.00 mm), or 0.250” (6.35 mm) with the number of turns being 1, 10, 11, 15, 20, 21, 30, or 100.