Because of the gap between {TAIL ~ the insulating ring} and {HEAD ~ the target}, high cost Boron Nitride insulators are not required and low cost porcelain insulators can be used 
Because of the gap between { TAIL ~ the insulating ring } and { HEAD ~ the target } , high cost Boron Nitride insulators are not required and low cost porcelain insulators can be used
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH