Slip on flanges with boss and slip on flanges with hubbed or neck, slip on flanges norms DIN EN1092-1 BS4504 pressure PN10 PN16 PN25 PN40, slip on flanges norms ANSI B16.5 class 150 300 600, slip on hub flanges norms JIS B2220 and KSB1503 pressure 5K 10K 16K 20K, slip on flanges manufacturer hyupshin flanges co., ltd