The Auto Hydrostatic Re-Arm Kit contains everything necessary to re-arm your Mustang Survival Auto Hydrostatic inflatable PFD after deployment.For model numbers: MD5183, MD5183 BC, MD5153, MD5153 BC.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.