My experience only is with one Voit 1/2" J valve from a 1956 stamped tank bought by me new in 1957. Voit is nowhere on the valve. It has the number 9155A, 2-56, Made in USA, patent # 2598248. The face where U S Divers is normally on their valves is blank. I have no knowledge if this was normal for all Voit 1/2' J valves with the 1/2" thread.