Rear Brake Cylinder Thread Size?

[joesturdy]

Just wondering what size the thread is on rear brake cylinders?

I'm ordering some connectors to fit braided hoses and want to get it right, the choices I've got are:

M10 x 1

3/8 x 24 UNF


Thanks!

[Lewis.]

M10x1, 10mm long with a lead in

[joesturdy]

Thanks!