A plurality of annular ridges are formed inside {HEAD ~ the passageway} at {TAIL ~ the distal end} of the cylinder 
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A plurality of annular ridges are formed inside { HEAD ~ the passageway } at { TAIL ~ the distal end } of the cylinder
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH