This great Sherwood reliable 80 cubic foot aluminum tank is GREAT for most diving needs. **You can opt to replace this with an upgrade to a converter valve. Sherwood is well known for its expertise in diving cylinders Built from proprietary alloy 6061-T6 Catalina tank manufacturer Meets all DOT and TC regulations 3000 PSI about 11.1 liters 77.4 cu ft capacity -1.8 lbs negatively buoyant when full 2.6 lbs positively buoyant with 500 psi 31.6 lbs when empty 7.25 outside diameter 25.1" Cylinder length K Valve included** Standard yoke outlet 3/4" -14 NPSM inlet 3000 PSI K Valve When ordering multiple tanks, please create separate orders for each tank or call us at 858.581.2800 to order, to ensure accurate shipping rates