The flange includes a first portion 12 of acetal material and a second portion 14 of an acid resistant material provided directly over {HEAD ~ at least certain regions} of {TAIL ~ the first portion} 12 
of
The flange includes a first portion 12 of acetal material and a second portion 14 of an acid resistant material provided directly over { HEAD ~ at least certain regions } of { TAIL ~ the first portion } 12
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 HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH