The miniature steppers come in diameters of 6, 8, 10, 12, 15, and 22 mm. Shaft sizes include the low friction-torque M1.2 X 0.25 mm, the extra fine M2 X 0.2 mm, and the M3 X 0.5 mm. All shafts come in various lengths and with optional self-lubricating nuts. Shaft tips accept a ball bearing for additional support. Specific units can include a quadrature magnetic encoder with 2,048 counts and a variety of gearboxes including zero backlash, exactratio planetary, spur, and hybrid. All versions resist back driving permitting removal of power after movement to conserve energy and limit thermal buildup.