5matl aluminum 356, sylc 239-900; protective finish chromate, mil-c-5541; dia., 1st side 1.3745 in. Min. 1.3755 in. Max. Od, 0.682 in. Min. 0.702 in.Max. Id, 2nd side 1.060 in. Min. 1.061 in. Max. Od, 0.776 in. Min. 0.786 in. Max. Id; thread 0.112-40 unc