Stainless steel thermocouple probe holder nipple 1/8 - 10X1 made of steel in 3 pieces including sealing ogive.
Useful as a spare in case the original is lost.
For 3mm thermocouple probe
Thread pitch 1/8 NPT, also compatible with 10X1 pitch which can be easily installed on both steel and cast iron manifolds, thanks to the conical thread and can be screwed or welded on the manifold