● About 20-30 times more durable than Steel Pin Gauge ● T he coefficient of thermal expansion is smal（l 1/2 of steel, 5×10 － 6K － 1）so the changes due to temperature are small ● Less likely to be damaged due to high hardness ● Even if broken, dimension does not change (no burrs on broken edges) ● Economical--Periodic calibration is not required
