Imperial/metric spanner

[ratwing]

I haven’t seen one like this before, has anyone else? It’s Spanish, made by Adesa, has a 1/2” ring on one end and a 12mm ring on the other.

 

[harveyp6]

I have Acesa spanners myself somewhere, but not one like that, although I have seen the same thing with other makes.

 

[j_radcliffe]

It is for when you have a 5/16" fine thread Chinese nut. The head will be 12 mm instead of half inch. Commonly referred to as Chinese Grade in Australia!