Composite materials: including saturated resin and unsaturated resin.The unsaturated resin is divided into glass fiber reinforced plastic hand covering and molded resin cover.Molded resin covers include SMC covers and BMC covers.Saturated resin with SMC molding resin suitable for any environment and requirements.Fiberglass hand - coated manhole covers and BMC moulded manhole covers are suitable for light vehicles to pass through places and green belts.

Concrete: including silicate reinforced concrete manhole cover and magnesite concrete manhole cover.Magnesite concrete manhole covers have been eliminated from the market and are not recommended for use anywhere.Silicate reinforced concrete manhole covers because of manufacturing standards vary, so the quality is uneven, such as the use of high grade cement products, with steel hoop and other strengthening functions, this product can reach the national standard C250.But the general ordinary label of the reinforced concrete manhole cover, can only reach the national standard B125, only suitable for light vehicles and green belt, and is not high to the aesthetic requirements of the place.

5 plastic: plastic inspection well supporting products, plastic inspection well is allowed to press there, can press there, can not be used alone