composite manhole cover Made by high-performance modified SMC sheet material through a high pressure pressing, the polymer ma Composite Manhole Cove Material: Sheet ... B125(12.5 ton), C250(25ton), D400(40 ton), E600(60 ton), F900(90 ton). SMC manhole cover is made from fiber ... glass reinforced plastic, the main materials are fiber glass, resin and quartz. ...