Cylindrical; c/o brass jewel mount, red syn sapphire ring jewel; 0.250 in. Nom dia; 0.125 in. Nom thk; countersunk hole 0.218 in. Nom dia; center hole 0.03000 in. Min to 0.03003 in. Max dia, with diameter having high olive crown; other hole 0.060 in. Nom dia; ring jewel 0.090 in. Nom dia, 0.020 in. Nom thk