Another advantage of the invention is that the glass core can be substantially centered with respect to {HEAD ~ the larger diameter exterior surface} of {TAIL ~ the second sleeve} 
Another advantage of the invention is that the glass core can be substantially centered with respect to { HEAD ~ the larger diameter exterior surface } of { TAIL ~ the second sleeve }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL