High-quality 22 cu ft aluminum oxygen cylinder. Up to 40% lighter than steel without sacrificing tough performance. Brushed aluminum finish with cranberry painted dome. Tank has great low temperature delivery. Guaranteed date of manufacture or hydro test within 12 months. DOT approved. Doctor's prescription required to fill with medical oxygen. Seek the advice of a physician if you have questions about the proper use of medical oxygen. Please be sure to use a regulator that fits the cylinder valve, and that is correct for your application of use. Product note: compressed gas cylinders can be dangerous if used improperly. Please be careful, know the correct procedures for use, and exercise caution when connecting and using any compressed gas device.