Aluminum Oxygen "D" cylinder. Capacity 15 cubic foot of oxygen. With wrench operated CGA 870 oxygen pin index post valve inserted. Cylinder has green dome with brushed aluminum sides. DOT 3AL and TC 3 ALM, 2015 PSI cylinder. 5.4 lbs empty weight, 4.38 inch diameter, 16.7 inch length, .750-16 UNF inlet thread. Manufactured from high strength aluminum alloy 6061-T6. Both the cylinder and the valve are manufactured in the US.