Aluminum alloy, black anodize, 0.020 in. Thk material, 1.312 in. Dia, two mounting holes 0.094 in. Diameter 0.312 in. C to c, one hole for shaft 0.190 in. Dia, numerals 0 through 9 placed at 36 degrees intervals cw, numerals tritium actived illuminous green, surface background lusterless black