The depth micrometer masters - models ADM are available in both inches and millimeters.
The inch range is .500" ‐ 5.500" in 1.00" steps +/‐ .0001" and 6.5" ‐ 11.50" in 1.00" steps +/‐.0002".
The metric range is 12.5 to 137.5mm in 25.0mm steps +/- .0025mm and 162.5 to 287.5mm in 25.0mm steps +/- .005mm.
The depth micrometer masters are case hardened, stabilized, ground and lapped. Depth micrometer masters are used to calibrate depth micrometers. The depth micrometer master is superior to Gage Blocks calibration because they eliminate the requirement to stack gage blocks. Using the masters is faster and more efficient for inspecting the linear range of the tool.