Yes, it's a Pivo stem. This one looks like a good casting. Check out this link:

http://www.bikeforums.net/classic-vi...l#post18038464

Making the simple modification to the top of the expander split will help to reduce the possibility of the stem breaking off at the bottom. Also stems need to be inserted at least 75mm to 80mm (~3") into the steerer!

Millions of cast aluminum stems like these were produced between the 1940's and early 1970's. Most have worked without any problems... They're OK for casual use on smooth roads with lighter riders. For more demanding riding, I'd recommend a forged aluminum stem with modern alloy bars.

verktyg

Chas.