Aluminum alloy qq-a-250/8 5052 ; 0.062 in. Thk; chromate mil-c-5541 cl 1a; 3.750 in. Lg; 3.250 in. Wide; 0.125 in. Radius corners; 2 holes 1 in each corner 0.139 in. Min 0.145 in. Max dia; cover has printed on it /warning ac line voltage beneath this barrier/