Steel, cmpsn 1045, astm a576 or steel, cmpsn 1137 specification qq-s-637, length 5.470 inches, width 4.613 inches, 2 holes 0.281 diameter and 2 holes 0.138-32un-3bx, large holes, from hole to hole is 4.50 inches, small holes, from holes to hole is 1.190 inches, diameter of circle is 3.97 inches.