1. Product model: -18 stepper motor controller; there are optional stepper motor drivers in our shop; video demonstration2. Function introduction: You can click positive and vice versa; press the forward button; press and hold the forward button; solve the stop; press the reverse button; press the reverse button; release the stop; self-lock positive and negative; push the potentiometer forward ; Press again to stop; press again to reverse; press again to stop;3. Rotation speed range: 0.1-999rpm; the last set speed is unforgettable after failure, worth a try.4. Interface description: DC +, DC-: DC 8~24V supplyMaterial:Plastic + Metalcolour:As ShownPackage Contents:2 x motor controller2 x driveOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.