A press is mounted to the base to selectively press {HEAD ~ the press block} against {TAIL ~ the gasket} and hold it in position 
against
A press is mounted to the base to selectively press { HEAD ~ the press block } against { TAIL ~ the gasket } and hold it in position
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH