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