... *300mm 3.Sand casting 4.Black Bitumen Coated Specification of manhole cover: 1.Material:Grey iron HT200 2.Size:300mm*300mm 3 ... .Sand casting 4.Black Bitumen CoatedSpecifications of the Square Manhole Cover:1.Material:Grey iron HT2002.Size:300mm*300mm/400mm*400mm3 ... .Sand casting4.Black Bitumen Coated We can also produce Manhole cover as followings:1. Standard: A15, B125, C250, D400, E600, F900 ...