Help identifying a socket

[Frito_Bandito]

I inherited a few tools from my father in law who was a mechanic back in the 80's and amongst all the snap on and Porto and other assorted brands I found a full set of 6 point metric 1/2" drive sockets (the only metrics he had) there's no brand name or any markings other than size and a single groove near the bottom and the word Taiwan next to the size marking. They seem well made and I use them daily (Toyota technician) and people always ask me about them when they borrow them because they're heavy and feel nice in the hand. Does anybody know what they are?

 

[3baygarage]

It's a generic Taiwan. With no markings it's impossible to come up with a brand.