5steel casting per qq-s-681; enamel od finish per tt-e-529 or tt-e-485; 4.062 in. W by 4.062 in.H by 0.531 in. Thk; 2.874 in. Id; countersunk 0.100 in. Deep by 3.190 in. Dia; 4 holes equally spaced 3/8-24unf-2b thds on a 3.889 in. Diameter bolt circle