Most of the prior art designs utilize a metal or ceramic ring around {HEAD ~ the outer edge} of {TAIL ~ the target} to confine the arc, allowing the arc to travel right up to the ring 
of
Most of the prior art designs utilize a metal or ceramic ring around { HEAD ~ the outer edge } of { TAIL ~ the target } to confine the arc , allowing the arc to travel right up to the ring
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD 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