It appears to be a Japan industrial pipe fitting standard. J identifies a group of adaptors with hex line fittings, OB is a class for adaptors for different sized threads on each side, and L is a specific type. 10 is a size.
Size 10 couples a 1-14UNF fitting to a 7/8-14UNF fitting..
This is a little bit of a guess tho.....
How big is the wrench?