and high quality. Bipolar constant current chopper High-speed optocoupler signal isolation input Electrical input signal is TTL compatible Stationary current is automatically reduced by half Suitable for any small-and-medium automatic equipment with CNC controller, such as X-Y-Z tables, labeling machines, laser cutters, engraving machines, and pick-place devices. Color:black Material: metal Supply Voltage: 9~42VDC Input voltage: DC 12 ~ 48V Operating Temperature: -10 to 45 ˚Degrees Celsius Storage temperature: -40 to 70 Degrees Celsius Max Drive Current: 4A Chopping Frequency: 20KHZ Package Contents: 20 x 4A TB6600 Stepper Motor Driver Controller 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.