SainSmart A4988 Stepper Motor Driver for Arduino Mega2560 Mega1280 RepRap Ramps</br></br><div style="text-align:left"><b>[Product Information]</b><br><ul><li>Simple step and direction control interface</li><li>Five different step resolutions: full-step， half-step， quarter-step， eighth-step， and sixteenth-step</li><li>Adjustable current control lets you set the maximum current output with a potentiometer， which lets you use voltages above your stepper motor"s rated voltage to achieve higher step rates</li><li>Intelligent chopping control that automatically selects the correct current decay mode (fast decay or slow decay)</li><li>Over-temperature thermal shutdown， under-voltage lockout， and crossover-current protection</li></ul></div></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br><img src='http://ecx.images-amazon.com/images/I/51KXgsKP%2BGL.jpg' noproxy></br>