... Grey iron:HT150,HT200,HT250,D400,E600,F9 Ductile iron manhole cover 1)ductile iron QT400/18,QT450/10,QT500/7,QT600 ... ,HT200,HT250,D400,E600,F9002)Loading weight of pressure:A15,B125,C250,D400,E600,F9003)Certification of quality:ISO9001:20004)Main ... Class B125, C250, D400, E600, F900 meeting the relevant EN124, BVQI and Australian standards 4) Form and Sizes available: square, rectangle, round ...