You need to look at the numbers stamped into it and find out what the working pressure is. Catalina makes both high and low pressure cylinders. Go to
http://www.catalinacylinders.com. You can email them with your info off the tank or you can call them at (714) 890-0999 and give them the info off the tank and find out from them what the working pressure is.
Their corporate headquarters is in Garden Grove California. Lucky for you, they're in-state. I've just emailed them to get a list of dealers in the Atlanta area who carry their scuba tanks. I'd really like to get a pony tank without getting cornholed on the price.
Wish I could buy the tanks from them for wholesale cost.
Remember, the only stupid question is the one you didn't ask. We're all here for a common cause, and I, for one never mind answering a question if I can.
Sorry I couldn't answer your question, but I was able to give you contact info for those who can.
Have a good weekend.