I have an interesting pressure indicator/gauge that I am hoping someone can identify. Please let me know if you know the manufacturer and year of production. The end piece is a spring-loaded piston with colored bands to indicate relative pressure in your cylinder... plus it has an audible alarm when you get low on pressure. Actually sort of a rude noise. I think this might be a good way to dive in a vintage mode and still monitor pressure. I just overhauled it and it works great.