1. 24V-50V DC power supply, 8 level adjustable output current 1.0A-5.6A. 2. Bipolar constant current PWM drive output. 3. Optical isolation input signal, pulse response frequency up to 200kHz. 4. Strong anti-interference capability, achieve high precision positioning in complicated environment. 5. Low speed zero vibration, and low noise. 6. Fit for 42/57 stepper motor and widely used in automatic packaging machine, engraving machine and other automation equipments. Specification: Application: 42/57 stepper motor Input voltage: DC 20-50V Output current: 1.0-5.6A, 8 level adjustable, 0.5A resolution Drive method: Bipolar constant current PWM drive Pulse response frequency: 200kHz(Max) Insulation resistance: more than the 500MΩ Insulation strength: 500V/min Colour:black Material:PCB+ABS Size:12 x 7.8 x 3.5cm Package Contents: 2 * DM556 stepper driver Only 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.