Another period torque wrench

[Keith True]

While reading the old torque wrench thread a couple of weeks ago,the one in the pictures looked kind of familiar.when I got in my Tudor today I found this one on the floor,I kind of forgot I had thrown it there for safekeeping about 10 years ago.It is a Sunnen model PN 50.I really don't know just what vintage it would be.I was given this with a bunch of tools by a man that bought them all new.