I just picked this up at a local yard sale for $0.25, any idea what went inside of it and who made it?

Hello, Moparthug. I am going to guess that the long tapered area held a wrench handle that would hold different size heads, or, inserts. The heads would fit in the corresponding smaller sections. I don't recognize the names, but I see a little bit of Xcel. Possibly Park Metalworks? Regards, Lou

This

Thanks Bill, that's the beastie right there!

Now I'm not positive but I always understood that Park Metalware made those sets and were marketed as Xcel multi-head wrench set. I would venture to say that that top decal is the name of the reseller.