The B230F EGR pipe piping is 12mm OD. It uses DIN 2353 compression fittings with M18x1.5 compression nuts. The EGR valve inlet and outlet is M18x1.5. The threaded port on the B230F manifold is M16x1.5 (I see some reports this is M18x1.5, maybe on turbo/90+?) The hexes on all the union/compression fittings are 22mm and the mount bracket nut is 24mm.