This is a compression union with an olive for mounting our Fan Thermostat (part no: #STAT)probe
into a female 1/8" BSP thread.
It is plated steel and has a parallel 1/8" BSP male thread.
Both hex are 14mm.
Can be used as a compression fitting for other 1/4" or 6mm diameter copper or steel tube.
Bottom picture shows probe on union for illustration. PROBE NOT INCLUDED
1/8" BSP THERMOSTAT PROBE UNION #STATUN2