Application for aluminum alloy thick workpiece. Hardness range 0 ~ 20HW. Min. reading 1HW.
Accuracy ?0.5HW (at 5 ~ 17HW).
To measure the hardness of soft metal such as aluminum alloy, copper, brass, soft steel, etc.
According to ASTM B647-84 (2000).

Insize 4130-18, METRIC THREAD PLUG GAGE, M18x2.5, 6928640340093 