"ALUMINUM QQ-A-355 ALLOY 2024 T4,5.000 IN. LG,4.000 IN. W,0.250 IN. O/A THK,APERATURE DIA 3.000 IN.,COUNTERBORED WINDOW RECESS DIA 3.406 IN.,4MTG HOLES 0.189 IN. DIA LOCATED EA CORNER,4 WINDOW RETAINING 0.112-40 2B UNC HOLES EQUALLY SPACED ON 3.625 IN. BOLT CIRCLE"