"Inmaterial aluminum alloy, MIL-S-22499, Composition 1, Type 1, Class 1, 3.426 in. ID, 4.140 in. OD, 0.048 in. thickness, five 0.156 in. mounting holes, and a 2.652 in. distance between mounting holes. One mounting hole is located 1.520 in. from the center."