* asme/ansi b16.47 : welding neck flange, blind flange. (series a & b) Pressure class : 75, 150, 300, 400 , 600 , 900 Pressure class :300, 400 , 600 , 900 * api 6a : welding neck flange, thread flange, blind flange. * size:1/2"-48"as 11000*11000*11000