ISO 6H thread Plug gauge gauges M18 M18X2.5 M18X2 Metric Fine Internal Threads gage M18X1.5 M18X1.25 M18X1 M18X0.75 M18X0.5

ISO 6H thread Plug gauge gauges M18 M18X2.5 M18X2 Metric Fine Internal Threads gage M18X1.5 M18X1.25 M18X1 M18X0.75 M18X0.5

Aliexpress UK