This gearbox has a 15:1 ratio with a .75" keyed output shaft. The NEMA 23 brushless motor is a large industrial unit made by the German company Heidolph. It can be replaced by any NEMA 23 servo. motor, or stepper. The internally keyed shaft can also be used to drive the unit. All belts and gearing is tight. No play or detectable backlash.
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Motovario 15 1 Gearbox w NEMA 23 Motor Mount | eBay