SOSpenders autoinflate in rain?
Everyone is right, to some degree. I have used my SOSpenders equivalent on and off. Just be very careful to always ensure the SOSpenders (or any other autoinflatable) is the LAST LAYER to be put on, and the first to be taken off. Long story short (not mine, but in the Hobart disaster race) you don''t want it to inflate under a restrictive jacket. It can crush your rib cage.
I had mine on in a blinding rain stornm, visbility less than 100 yards. No problem. Two days later while bending over, it inflated automatically and I didn''t know what it was for the first 2 seconds and I darn near had to change my pants. The regimen I use now is I use it in manual inflation mode, unless it looks like nasty weather, and then I reArm it for automatic. Most accidents I read about where people are lost is either no PFD or they were knocked unconscious and overboard. (yeah, harness, but that''s another topic).
I have found by shopping carefully both the "Bobbins" and the "CO2" bottles can be purchased separately and much more cheaply than the "kit". One Caution. The Date marked on the "bobbin" is one year before the expiration date, and many stores put them on SALE just before they expire. The included instructions explain both the Dating of the bobbins, and the periodic inspections which should be done (mea culpa). Some people learn the hard way! (Who me?) BTW - Don''t expect all chandleries to have knowledgable staff or that they all know the difference. I have a passion for opening stuff and reading before I buy it.