Iverntech NEMA 17 Stepper Motor with Integrated 400mm Tr8x8 Lead Screw, much stable than shaft coupling connecting High torque nema 17 stepper motor, 400mN.m/57.1 oz.in, 42mm, 2 phase 4 wires Come with a brass nut and 1M (39.37") motor wire 2mm pitch, 4 starts, 8mm lead Great replacement for the Z axis of prusa i3 3d printers