Parts of the vest
Each vest has a number of indispensable parts, so you can fasten the vest and have all the necessary parts to make a safe dive, think of D-rings and fastening clips for console or octopus.
Your jacket/trim vest is also connected to your breath regulator by means of the inflator hose, which works on medium pressure of this regulator. There are several buttons on the inflator unit. When you press one button, air comes in your vest, you press the other button, then the air goes out of your vest. In addition to these breather valves, there are often three other valves to allow you to quickly breathe your BCD in any desired position under water. Quick venting is necessary, because otherwise you would rise to the surface too quickly.