Hobbypower StepStick 4-layer DRV8825 Stepper Motor Driver Module for 3D Printer Reprap RP A4988(pack of 5 pcs) + 1 Hobbypower strap This DRV8825 Stepper Motor Driver Module is upgrade of A4988 Simple step and direction control interface 4-layer, 2 oz copper PCB for improved heat dissipation Six different step resolutions: full-step, half-step, 1/4-step, 1/8-step, 1/16-step, and 1/32-step Adjustable current control lets you set the maximum current output with a potentiometer, which lets you use voltages above your stepper motors rated voltage to achieve higher step rates