Brass qq-b-613 comp 1 or 2 1/2 hard; 0.014 through 0.018 in. Thickness; 1.898 through 1.903 in. dia; 0.786 through 0.791 in. Inner dia; one hole 0.125 through 0.130 in. Diameter on 0.750 in. radius; chemical treat per montrose process specification no.56 (entek cu-56)