Magnesium alloy; anodized mil-m-45202 type 2 cl a gr 4 and mil-m-3171 type 3; 2.450 in. Min 2.460 in. Max h; twelve 0.201 in. Min 0.206 in. Max holes equally spaced on 9.250 in. Diameter bolt circle; sixteen 0.220 in. Diameter holes equally spaced on 7.125 in. Diameter bolt circle