ANSI / ASME B16.5 Backing Ring Flanges Manufacturer, Backing Ring Flange Dimensions
Ideal Vacuum | ASA 4.25 / ANSI 1 Blank Flange, with O-Ring Groove, Not Bored, Not Rotatable, 4.25 in OD, 3.125 in BCD, Four 0.625 in ID Bolt Holes, 304 Stainless Steel
AWWA Class SB Stainless Steel Ring Flanges - API International, Inc.
Backing/Back up Flange, Stainless Steel Backing Ring - Manufacturers