http://cabelas.com/cabelas/en/templa...l&N=4887&Nty=1
this looks like the newer updated version.
It is all manual, so if you hit your head or something you are sol. It has a loop that comes out and you put over your head.
Luckily I haven't had to use mine, but last summer I put on my waders , surftop, and inflatable and went swimming to see how it felt.
It took a long time for my waders to fill, since I wear two wading belts, one just over my waders, one over my top and the inflatable. not until i dove down and swam along the bottom could i feel water start to fill me up.
I was actually pretty buyont with all of the air in the waders and top. i stayed there floating for about 30 minutes before i got bored and started trying to swim.
In that instance I never inflated the pfd, but I would recomend trying it on and manually inflating it while in the water to see how to put it on.