The Auto Hydrostatic Re-Arm Kit contains everything necessary to re-arm your Mustang Survival Auto Hydrostatic inflatable PFD after deployment. Contains an Auto Hydrostatic Inflator, which includes: Cap Body 33gram CO2 cylinder Metal key Re-arming instruction manual For model numbers: MD3153, MD3154, MD3183, MD3184 and MD3188 Use only Mustang Survival re-arm kits Use of other re-arm kits may result in improper operation, or failure to operate, and will void the product&';s warranty Regular maintenance can reduce the possibility of inadvertent inflation. Refer to your Owner&';s Manual for maintenance schedule The Auto Hydrostatic inflator cap and body should be replaced before the expiry date on the cap passes