The Stanley Hex-a-Matic. Everybody was trying to cash in on "a-matic" in the Sixties.
Note the nested collets, intended to grip different sizes of nuts or bolt heads:
It was clearly designed to compete with other similar tools like the Ideal Sock-o-Matic wrench featured in a previous blog entry. Here's how Stanley advertised it back in the day:
I've had this tool for ages, and I don't think I've ever used it. It's simply too ungainly, especially for smaller fastener sizes. I usually just grab the standard nut-drivers, even though it means messing around to find the correct one. (See Mister G's previous post on Spintite.)