{TAIL ~ 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 the center of {HEAD ~ the waist} 
{ TAIL ~ 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 the center of { HEAD ~ the waist }
TAIL 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 OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD