A unitary integral tank for fluids, such as air or other gasses in diving tanks, having one end thereof formed to be self supporting or standing and the other end thereof tapped for threaded engagement with valves; the cross section of said tank being substantially circular with thickened end portions for strength. The tank is fabricated from a stainless steel material containing in excess of 16. 5% chromium, and in excess of 24% of chromium, manganese and nickel combined.