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