1、This driver board adopts of a new type of polar double-constant current chopper technology 2、The motor driver board has the automatic half-current function 3、The maximum input pulse frequency is 150KHZ 4、Support the following subdivision selections: 1, 1/2, 1/4, 1/8 and 1/16 5、It has the stepless adjustable function of current 0.5~4A Features: This driver board adopts of a new type of polar double-constant current chopper technology The motor driver board has the automatic half-current function The maximum input pulse frequency is 150KHZ Support the following subdivision selections: 1, 1/2, 1/4, 1/8 and 1/16 It has the stepless adjustable function of current 0.5~4A Beautiful and generous shell, anodized sandblasting treatment. 4 channel stepping motor drive, convenient for wiring, the back of the heat sink back  is punched with threaded hole, convenient to install. Specifications: Max. pulse frequency: 150KHZ Current: 0.5~4A Size: 16.2* 8.8* 3.1cm/ 6.38* 3.46* 1.22in Weight: 339g Package includes: 1 x Motor Driver Board