Material:cast iron astm-a48,class 50;5.375 in.Square;4.250 in. Thick;center hole 7.750 in.Dia;four mounting holes 0.3125-18 unc-2b;6 additional holes equispaced 120 degreeapart (two sets of three holes in line);surface finish:finish mil-c-8514and 24.17 of mil-std-171;color gray no. 36440 of fed-std-595