Both of these aluminum oxygen tanks had over 2000 psi of oxygen in them until I emptied them recently. The valves have been loosened and removed on both tanks and are loosely screwed back in. The tanks are 4-1/4” in diameter and 25-3/4” tall. One tank is a stamped suggesting that it was certified most recently in 1995. The other one appears to be from 1999. Not recommend for health use. Would be great sor use as portable air tanks.