... ,321ss, etc.) Materials: 304, 304L, 306, 306L, 317, 317L, 321 and 904L stainless steel Types: WN, BL, PL, SW, SO ... and RF Relative Standards of Flanges: 1) DIN DIN 2573 PN6 ... ") PN: from PN6-PN100, 150LBS-2500LBS Sealing Surface: F.F., R.F., and R.T.J., FM, Lap Joint