You won't even notice wearing the vest, until you fall. When you fall the spiral cord will be pulled from the airbag vest and the CO2-cartridge will be activated, releasing the gas which fills the vest in approximately half a second.
When the vest fills, you will instantly have the feeling an enormous unbreakable balloon is wrapped around you. Above that, your neck will be surrounded by the neck roll, this will reach from your ears to the underside of your cap. Your body, with all its vulnerable and vital organs, is protected from your neck to your coccyx and hip joints. You are indeed fully packed!
All of this will take place while you fall, fast enough to give you a soft landing.