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