"ALUMINUM ALLOY MATERIAL; ANODIZED HARD PER LAC PROCESS SPEC 445 TYPE II,ALL OVER; 0.289 INCH MINUMUM,0.302 INCH MAXIMUM DIA OF HOLES; 4 HOLES EQUALLY SPACED TO EACH OTHER WITHIN 0.005 INCH; 3.595 INCH MINUMUM; 3.605 INCH MAXIMUM DIAMETER OF CENTER HOLE CIRCLE"