Genuine Watterott TMC2208 Stepper Motor Driver & Heatsink.

Further infos on the GitHub project page: github.com/watterott/SilentStepStick 
 
Features
Hardware compatible with StepStick and Pololu A4988
Drive capability up to 1.2A (RMS) continuous coil current - 2A Peak
Step/Dir interface with microstep interpolation (up to 256 microsteps)
Configuration via CFG pins or UART interface
Motor voltage: 5.5...36V
Logic voltage: 3.3...5V
stealthChop2-for quiet operation and smooth motion (default setting)
spreadCycle-highly dynamic motor control chopper (enableable via UART)