All our covers and gratings are cast iron. The standard grade is ductile iron GJS-500-7 (GGG50), equivalent to ASTM A536 65-45-12, with tensile strength ≥ 420 MPa and elongation ≥ 10%. For light-duty A15 and B125 we can cast grey iron GG20/GG25 on request. We do not supply steel, composite or resin covers.