Inflatable PFDs provide buoyancy when their chambers are inflated. This happens when air or gas (usually CO2 from a cylinder) is discharged into the chamber or when the PFD is inflated by mouth.
Inflatable PFDs are available in three styles.
Manual (vest or suspender type)
Can be inflated manually by using a CO2 system or by mouth.
Manual (pouch type)
Can be inflated by mouth or by pulling the ripcord or toggle that activates a CO2 gas inflation system.
Automatic (jacket type only)
Automatically inflates when immersed in water. This type also may be inflated manually by pulling a toggle or ripcord. It is not permitted for sailboarding or white-water activities or for persons on PWCs because frequent immersions will cause premature inflation.