Function: Breathing muscle strength training can reduce shortness of breath and increase lung capacity, forcing you to focus more and breathe more deeply, thereby increasing lung capacity. Material: Made of soft silicone rubber nozzle and high quality ABS plastic, safe, reliable and durable. Adjustable: The resistance value can be adjusted to select the level of breathing and resistance you want, and more vigorous exercise can be performed as needed. Portable: Pocket-sized design, light weight, small and portable, can be used anytime, anywhere. Date First Available January 8, 2024