The ridges on {HEAD ~ the cylinder} snap fit into mating annular ridges in the cap to prevent re use of {TAIL ~ the needle} once the syringe is discarded 
The ridges on { HEAD ~ the cylinder } snap fit into mating annular ridges in the cap to prevent re use of { TAIL ~ the needle } once the syringe is discarded
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH