Who Manufactured the Firestone Wrenches?

Update 3/14/2016 - Based on the comparison of countless wrenches, we believe we can say that these wrenches are made by Duro.

 

Over the course of the next few days, we will be uploading numerous examples of wrenches in an effort to compare and identify the manufacturer of the Firestone wrenches.  These wrenches are very hard to come by, and we only have 2 in our collection.  Our primary suspects for manufacturing these tools are Duro, Fairmount and possibly Williams, but we will upload examples from most manufacturers in an effort to be comprehensive in our evaluation.