... Max pressure:A15,B125,C250,D400 4.Certification:ISO90 Cast iron Manhole CoverFeature:1 environmental protection with non-toxicity raw ... strong , durable .Our company specializes in the production of ductile iron manhole covers, rain olivier, W-type tube, the variety ... models. To adapt to the schools, hospitals, factories, community, the station, the airport and so on all sorts of public and ...