Part of SmoothStep line, Whisper Torque ZH417-11 Stepper Motor with Signature Series Technology can incorporate up to 11 mm ID hollow shaft and still maintain accuracy and torque. NEMA 17, 0.9° motor features patent pending design that has no magnet on rotor. Instead, motor uses ring magnet around stator coils that is sandwiched between stator stack. Since there is no permanent magnet in rotor and only outer edges of rotor are used, large shaft dimensions can be implemented.