{HEAD ~ The gasket} 18 is then positioned on {TAIL ~ the active surface} 16 of the substrate so that the central opening 19 in the gasket is fully within the window opening 21 of the base at a proper position, and the press block 13 is then positioned over the gasket 18 so that the engagement surface 20 properly seats against the gasket 18 
is positioned on
{ HEAD ~ The gasket } 18 is then positioned on { TAIL ~ the active surface } 16 of the substrate so that the central opening 19 in the gasket is fully within the window opening 21 of the base at a proper position , and the press block 13 is then positioned over the gasket 18 so that the engagement surface 20 properly seats against the gasket 18
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL OTH REL REL TAIL TAIL 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 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