This provides {HEAD ~ reliable operation} of {TAIL ~ the arc} for a wide range of the cathode sizes and shapes, and at low to very high power levels 
This provides { HEAD ~ reliable operation } of { TAIL ~ the arc } for a wide range of the cathode sizes and shapes , and at low to very high power levels
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH