Ductile iron manhole cover 1)ductile iron QT400/18,QT450/10 ... :HT150,HT200,HT250,D400,E600,F9 Ductile iron manhole cover 1)ductile iron QT400/18,QT450/10,QT500/ ... ductile iron and grey iron manhole covers and grates 2) We also produce drain cover using steel, stainless steel ... and Australian standards 4) Form and Sizes available: square, rectangle, round, from 200mm to 1200mm 5) Certificate of Approval ...