What is an RTJ Flange? | Ring Type Joint Flanges (PDF) - What is Piping
O-Ring Flange (3" Series)
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