Pack of 6: Comes in 6PCS BTT TMC2209 stepper motor drivers and heatsink. Thanks to the StealthChop2, TMC2209 drirver serves as ultra-quiet stepper motor driver with with a continuous current of up to 2.0A (with peaks of 2.8A). Voltage ranges from 5.5V to the maximun output of 28V. Ultra-Silent: The StealthChop2 allows for no-noise, high-precision chopper algorithm for inaudible motion and inaudible standstill of the motor, making it super quiet during printing. And the flexible microPlyer interpolation unit provides up to 256 subdivisions, which can achieve perfect sinusoidal control even in systems with limited pulse frequency.