When selecting a PFD the most important consideration should be the size and approved for your weight range. There are different types of PFD; the first has the most flotation at 22lbs of buoyancy, it keeps unconscious persons head up but is fairly bulky. Type 2 has less flotation and may keep persons head up but again is bulky and uncomfortable. Type 3 is what is weared by people who do skiing, it doesn't keep unconscious persons head up but is the most comfortable and likely to be worn at all times to count.
