{HEAD ~ A glass} to {TAIL ~ metal seal} is formed between the insulative preform 12 and the metal package 14 at the aperture 16 to provide a hermetically sealed package 
to
{ HEAD ~ A glass } to { TAIL ~ metal seal } is formed between the insulative preform 12 and the metal package 14 at the aperture 16 to provide a hermetically sealed package
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 OTH OTH OTH