Brand New Adjustable Breathing Resistance Trainer for Athletes & Musicians Resistance Trainer. Lung Exercise Device. Expands and restores Lung Capacity Variable Breathing Trainer with 100% Grade Silicone Mouthpiece Advantages and preferences: Classified and evaluated by testimonies of athletes and people who compare them with other similar devices. Lung Trainer Breathing Exercise Device has exceeded, in functionality, optimal results and satisfaction in their daily use. It has compact composition and tight dimensions of 2" x 3.25" inch with its low weighting of 1.42 oz. make it a comfortable and easy regulatory adjustment