api 5000Beware, some suppliers and manufacturers supply normal A105N 36K material flanges stamped as 3,000 or 5,000, these interconnect with API sizes (example a 2 ANSI A105 1500 class flange rated at 3,700 psi CWP is the same asPressure Rating:- API 6BX-2000 PSI WP (With BX type Ring Gasket) Nominal Size B Flange Thickness T Hub Diameter J1 Groove Depth E Added Hub Thickness J4 263⁄ 4 30 4.97 5.28