The Airofit Breathing Trainer Bluetooth Mouthpiece increases your lunge capacity to improve your breathing technique. As a result, this breathing trainer makes working out feel a little easier. If you spend a lot of time exercising, this smart device helps you to build healthy lungs. It works by providing adjustable airflow resistance. Consequently, your respiratory muscles have to work overtime. In fact, you can adjust the settings to suit you. For example, choose the duration, training program, and intensity you..