I was lucky enough to see a demo first hand.
The inflatable vest is literary a vest and has no sleeves. The demonstrator wore it on top of a long sleeve shirt and blew it up a few times. The vest is supposed to fully inflate within like 0.3 seconds, but a couple times the demo vest took about 0.5 seconds or longer to inflate. Is it reliable?
The CO2 is released when a cable (hooked to the bike) yanks the trigger valve on the capsule - just like how a grenade goes off. You have to hook yourself to the cable when you get on the bike and unhook yourself when you get off (otherwise "KABOOM").
Now, I was thinking, this thing inflates quite a bit. The cushion looked like about 3 inches. I don't know if it has enough space to inflate inside my riding jacket that already has quite a bit of protective armor. Then again, I'm not that skinny... Wearing the vest on top of a jacket is possible, but you know, a vest on top of a jacket just doesn't look good.