KSB1503 is Korean flanges standard, flange pressure have 5K 10K 16K 20K 30K etc, flange type plate flat flange, blind flange, hub flange, sealing face raised face RF, flat face FF, carbon steel SS275, SS400, A105, Q235 etc, KSB1503 is the same as JISB2220, so KSB1503 flanges and JIS B2220 flanges can instead of each other.