This cartridge contains CO2, an inert gas used to inflate marine safety gear such as inflatable life jackets, life rafts, and man overboard buoys. You are welcome to read about why this gas is commonly used. This CO2 cylinder has a ½″ threaded end. You might keep a couple of these on hand as spare parts inventory. This is the same cylinder included in the dan buoy recharge kit and is also used in inflatable life jackets with the Halkey–Roberts V90000 / Alpha Inflator or the UML Pro Sensor Mark 2 inflator. This item can only ship via ground delivery (or local pickup).
Check the FAQs for answers to questions about the dan buoy.