providing {HEAD ~ a syringe plunger} having {TAIL ~ a first lock element} located only at its distal end 
providing { HEAD ~ a syringe plunger } having { TAIL ~ a first lock element } located only at its distal end
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH