I've seen 2 of the right angle drives in 60 years, one is mine. The other slipped away from me when the owner died and his fool wife passed his tools along to a "nice young man" who was following in her husband's footsteps.
The one you have is from the 70s, a second production, similar to mine.
They were NOT designed for high torque use, so use it accordingly. It's a tool that can save you hours in some miserable situations.