Also, {HEAD ~ the testing apparatus} uses {TAIL ~ the rotation} of a threaded rod to apply the force necessary to create the face seal 
Also , { HEAD ~ the testing apparatus } uses { TAIL ~ the rotation } of a threaded rod to apply the force necessary to create the face seal
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH