The digital control unit POWER UNIT II (PU II) by CHEYENNE complements the HAWK perfectly. It is very small and thus easy to transport. One or two machines, between which you can easily switch, can be plugged into the PU II. There are neither twisting nor sliding controllers which allows for simple cleaning. The frequency of strokes can be regulated in steps of 10 from 50 to 150 when the PU II is turned on.WARRANTY INFORMATION:Cheyenne Professional Tattoo Equipment provides precisely working machines and sophisticated technology.However, In the highly unlikely event you experience a problem with your product, warranty is directly covered by Cheyenne, we will give you instructions of how to contact Cheyenne directly to resolve your issue.