What size is the nut holding the outlet onto the back of a urinal

[Nobbyone]

Hi all,

I need to take a urinal off a panel to fit some plastic covering to the panel. Can someone tell me what size might be the nut holding the water outlet onto the urinal. It is an ideal standard.

Thanks

 

[ShaunCorbs]

1” nut if it’s the one onto the flush from the flush pipes to the cistern

Or do you have concealed ? Then it’s normally 1/2”

Picture might help

 

[Nobbyone]

It's the thin nut on the back of the chrome spout that I need to remove. It is recessed in the panel. I need a box spanner to undo it so that I can lift the urinal off it's brackets.