These training devices have been engineered to increase lung strength and capacity. the ‘O2 Trainer’ are small plastic training devices that have been designed for use while exercising. The training devices actually restrict and control the levels of oxygen that you receive during your training exercises like running, weight lifting or bike riding.
These training devices can be simply adjusted to different levels of difficulty depending on where you are with your health and breathing. Training with these devices is extreme and will strengthen your lungs and endurance; keep in mind that these training devices have been designed by the famous UFC fighter Bas Rutten and you should read all instructions and take care when working out with something like this, especially if you are a beginner.