I have one of those in a 5 or a 6/8. I haven't seen one in 3/8. Usually 3/8 razors were for haircutters. Some times they are marked 'special coiffure' or some such thing. You could shave with it but it probably won;t be as comfortable as a larger width blade. Puma began in 1769 and was family owned and operated through the years until somewhere in the early 1980s IIRC. Pumaknifeman has a website here with a more detailed history.