George, Happened to have one of those I haven't used in years. My fear is being in the middle of a lake by myself on a beautiful day, falling out, and watching the boat drift away. Doesn't take much of a breeze.
So, the CO2 cylinder is either punctured or it isn't. The indicator goes from green to red if the puncturing mechanism is in the puncture position. Decided to peel the Velcro apart and visually inspect. Lo and behold some user instructions were hidden in there.
These inflatables require maintenance by owner. SOSPENDERS should be checked for rips, tears or punctures between outings. To check for leaks orally inflate the bladder until firm and leave overnight. If the inflatable is damaged replace it. This model of SOSPENDERS uses a 38 gram CO2 cylinder. Each CO2 may be used only one time to inflate the PFD and then needs to be rearmed with a new rearming kit Refer to the Operating Instructions included in the Owner's Manual for Halky Roberts V86160 inflator specifications.
Refold the SOSPENDERS (see folding instructions) We highly recommend that SOSPENDERS be serviced by SOS, Inc. or any authorized dealer one year from the date of purchase and every year thereafter.
The instructions give a rearming kit model number, didn't include that above.
Anyway, clean and looks like new inside and out. No damage or age brittleness to the inflatable bladders. So put back together, back in a bag and to the garage shelf.
Note this is manual inflate only. Wouldn't trust the auto inflate more than a season but don't know, haven't looked into it. But humidity can't be good for the useful life of the actuator.