Steel, carbon, sae 1008 to 1020, temper 3 to 5, enamel olive drab finish, 0.036 in. Thk material, 15-1/4 in. O/a w by 21-1/4 in. O/a lg, w/attached welded angle bracket 14-3/8 in. From end across w w/two 11/32 in. Diameter mtg holes spaced 11 in. C to c along bracket lg