Ok Don, I'm betting you or any other members do not have this set?
They're from PEC (Products Engineering Company), Los Angeles, CA; I have no idea how old they are but I would say somewhere between '20-50's? Set size: 3/16" - 1/2"
PEC now a days makes excellent machinist squares and rulers that compare to Starrett, they also make ruler blades for Mitutoyo which I use daily.
I couldn't tell if it was the same company until I found this pic with the same current logo. The last pic is of a label of same vintage nut drivers I found online (not mine).
Not sure what I'm going to do with them, they've been sitting in a bottom drawer collecting dust but I might clean them up and de-rust them but saving the handle finish.