This heavy duty aluminum carbon dioxide tank is designed to hold CO2 and is great for use with a regulator, valve, CO2 controller or timer. With a plastic collar to prevent damage during shipping and use.The aluminum tank is roughly half the weight of standard steel tanks while still producing reliable results. These tanks do not come filled and allow the user to determine the pressure and mixture to be applied to their plants. Featuring standard tank fittings that easily attach to supplemental CO2 systems and fittings.These tanks are popular because they are not as heavy as steel tanks and do not rust. Manufactured in accordance with U.S. DOT 3AL and TC 3ALM requirements. Every cylinder is inspected and tested by a DOT and TC authorized independent inspection agency. 1800 PSI max fill pressure.