1 = HIGH PHOSPHORUS ELECTROLESS NICKEL per MIL-C-26074 CLASS 4, ASTM B733, min 10.2µm PLATING THICKNESS. PLUG ALL THREADED HOLES PRIOR TO PLATING.
3 = BLACK HARD ANODIZING per MIL-A-8625 - TYPE 2, CLASS 2. PLUG ALL THREADED HOLES PRIOR TO ANODIZING.
7 = Nickel electroplate, fully bright, 6.35µm thick, over Copper electroplate, 2.54µm thick.
8 = Hexavalent Chromium Chromate Conversion Coating to meet Mil-C-5541A standard. Restricted for some applications.
9 = Trivalent Chromium Chromate Conversion