api5000API 5000, 10000 are used in reference to wellhead 'christmas tree' pressure ratings as well used for the wing valve, master valve ratings. There may be hher classes asAPI6A (6BX) FLANGES Rating:- API 6BX-10000 PSI WP (With BX type Ring Gasket) Size OD T ØK PCD N Ød ØJ2 J3 BX 113⁄ 16 21⁄ 16 29⁄ 16 7.38 7.88 9.12 1.66 1.73 2.02