Originally Posted by JonathanJ

Right been out to garage and got my spare convertor , the manifold ( male ) end is 3/8th npt , ie 18 threads per inch (1.4 mm pitch) with a major diameter of just over 17 mm , the female end is M12 X 1.5 mm , ie the same size as wheel stud / nut threads if you want to check yourself .

Hope this helps .