Steel conduit thread; thread gauges, "go" and "not go" thread plug gauges.

钢制管螺纹。螺纹量规。过端和不过端螺纹塞规。

youdao

Steel conduit thread; thread gauges, "go" and "not go" thread plug gauges.

钢制管螺纹。螺纹量规。过端和不过端螺纹塞规。

youdao