This is a replacement, water-sensitive bobbin, for use with Inflatable Life Jackets. It can be used with any Halkey-Roberts inflatable life jacket that is bobbin activated.INCLUDES:Water sensitive bobbinRefer to your OWNER’S MANUAL for rearming instructions and bobbin usage. Store bobbin in a dry place.Inflatable life jackets can be reused after each inflation but the CO2 cylinder needs to be replaced before using again. Use an Onyx rearming kit to keep yours ready. It is recommended to purchase an extra rearming kit to try out your inflatable life jacket and become familiar with its operation. Be sure your inflatable life jacket is properly armed and ready to use before you head out on the water. Always read your Owners Manual for the proper way to initially arm your life jacket with the CO2 cartridge, and how to re-arm it after it has been inflated.