What size wrench to adjust Dahon D7 handlepost?
 

I want to tighten the nut that controls the folding of the handlebars.
It seems to require a rather small size wrench that is not in my tool box. Anyone know what size it is and where I could get it from without having to buy a whole new tool set?

it's a size 8.

I use a pair of needlenose pliers.

I also tried it with an adjustable wrench, a small one, before. In the end, I decided it was not worth risking the rounding of the nut so I went out and bought me a size 8 for $3, haha!