Empire paintball tank; I think it has about a year before it needs to be recertified.
I did some modification of the tank so the pressure was high enough to use with my airgun; this is 3000 psi so if you are not REALLY careful you could damage your paintball gun. That's why my price is ridiculously low. Below is a link to the Empire site; remember that the price on the website is for the bottle only; my price includes the fill hose, although it may not fit all paintguns.