aluminum 50 makes a great tank for both the technical and recreational diver. Technical divers appreciate the easy use of the tank for stage applications. Here are the specs for this tank. Service Pressure 3000 PSI True Capacity 48.4 Cu Ft Bouyancy Full -2.5 pounds Bouyancy Empty +1.1 pounds Empty Weight 21.3 Pounds Cylinder Length 19.0 inch