Restube consists of a bag that can be attached to the hip or trapeze. The bag contains an uninflated float. When danger threatens, you pull the cord, which inflates the float by itself using a CO2 cartridge. With this you keep your head above water! The yellow color can also attract attention from others if necessary.
This completely depends on what you want to do on the water. The Classic is suitable for many purposes and the Swim, Sports, Automatic, Lifeguard and PFD are designed for special purposes. The Swim and Sports are perfect for sports & competition and the Lifeguard and the Automatic are perfect for saving lives.
That's certainly possible. When you have used the Restube, you only have to replace the CO2 cartridge. When the CO2 cartridge has been replaced, you can easily use your Restube again.