... threaded, blind, slip on, lap joint are in accordance with ANSI B 16.5 from 1/2" to 24" ... and from 300 to 2500 lbs are in accordance with ANSI B 16.36.Blind, slip on, welding neck ... Flanges from 2kg to 210 kg are in accordance with JIS.Flanges according to API 605/ASME B16.47 ... P250GH,C22.85. Surface TreatmentAnti-rust Oil, Transparent/Yellow/Black Anti-rust Paint,Zinc,6. Inspection:factory in-house self ...