Bar: copper alloy 110 qq-c-502 .025 tk x .075 wide equal to 82s no. 16 gauge wire. Clip: beryllium copper qq-c-533 coa alloy 172 .008 tk. Heat treat to full hard (spring temper). Finish: gold plate per mil-g-45204 type ii .00003 thick over nickel plate per qq-n-290 .00005 thick