The Black Box series is LungTrainers’ newest breathing trainer device technology. The Black Box comes in four models, each adding an additional element for the user. All Black Boxes include a patented air sensor, pressure monitors, and one or more digital displays. These devices are powered by 4 AA batteries, ensuring portability and ease of use. Product Price:- $320.00 Shop Now:- https://lungtrainers.com/product/lungtrainer-black-box/