The micrometer set masters 01-1 are available in both inches and millimeters.
The inch range is .10-1. It is hardened, stabilized, ground and lapped to +/- .0001".
The metric range is 0 to 25.00mm diameter. It is hardened, stabilized, ground and lapped to +/- .0025mm.
Both are supplied in stainless steel to reduce wear and prevent rust.
The Micrometer set master has two odd steps at .512" and another at .712". These steps allow checking of parallelism of the micrometer anvils. Micrometer set masters are used to calibrate and set micrometers. The master is superior to gage block calibration because they eliminate the requirement to stack gage blocks. Using micrometer masters is faster and more efficient for inspecting the linear range of the tool. Micrometer set masters indicate the wear on the micrometer anvil because they replicate how the micrometer is used.