Oil Pressure Switch

[mark]

Does anybody know what the thread is on a standard 1.8cvh oil pressure switch?

I have a new pressure gauge and sender but the adaptor supplied is a smaller finer thread so i want to order another adaptor

I could go out in the cold take it out, dig out my thread gauges and find out for myself but i would rather sit in my warm computer room and finish my can of lager whilst someone else tells me the answer