3alum alloy per qq-a-601 comp 3, temp t71; proof test at 200 psig; 1.737 in. Lg by 4.000 in. Diameter o/a; 8 0.218 in. Diameter holes on 3.500 in. Diameter bolt circle; 2.120 in. Lg by 1.160 in. Wd flange w/2 0.199 in. Diameter mounting holes and one 0.375 in. Diameter bore