The product is compatible with ESD, EMI, EMC, adapts optical coupling isolation design and uses TVS for interface safety protection. Core chip all metal shield design. Description: Current can be adjustable With 5V power converter chip Over heat automatic protection With command heat sink method With SMD chip, high performance With half flow function when there is no pulse signal input Color: Black Material: Plastic, metal Size: Approx 4.17 x 3.39 x 1.34 inch/ 10.6 x 8.6 x 3.4cm Package Includes: 1 x Stepper Motor Driver