the annular shoulder is centered at an axial distance from the front end of the tip substantially equal to one half said axial distance of {TAIL ~ the center} of {HEAD ~ the waist} 
the annular shoulder is centered at an axial distance from the front end of the tip substantially equal to one half said axial distance of { TAIL ~ the center } of { HEAD ~ the waist }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD