{HEAD ~ Stopper} 26 may remain in {TAIL ~ place} so that at a next treatment hollow closed end needle only has to be pushed in so far that teeth 27 and 28 grip around surface 31 
remain in
{ HEAD ~ Stopper } 26 may remain in { TAIL ~ place } so that at a next treatment hollow closed end needle only has to be pushed in so far that teeth 27 and 28 grip around surface 31
HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL 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 OTH OTH