Large old aluminum Tri Clover open ended wrench from an old farm estate. This wrench is marked "Tri Clover - 25H-3 - Kenosha, Wisconsin". It was made for using with the stainless steel fittings on dairy farm milk bulk tanks, milking pipelines and related food grade stainless steel equipment.
Aluminum was used for these wrenches as aluminum is much weaker then stainless steel, so if the fittings became stuck too tight, the farmer would bend or break the aluminum wrench before the threads on the stainless dairy fittings would be striped.
This Tri Clover wrench measures 1 1/4" across the open jaws of the wrench and about 20" long. The handle of the wrench is bent and there is some damage to the outer edge of the one wrench jaw.