Unlike the prior art systems, {TAIL ~ the instant invention} imposes no limits on {HEAD ~ cathode size} or shape 
Unlike the prior art systems , { TAIL ~ the instant invention } imposes no limits on { HEAD ~ cathode size } or shape
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH