The gasket 18 is then positioned on 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 {HEAD ~ the engagement surface} 20 properly seats against {TAIL ~ the gasket} 18 
The gasket 18 is then positioned on 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 { HEAD ~ the engagement surface } 20 properly seats against { TAIL ~ the gasket } 18
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 HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH