- Adjustable resistance levels: this handheld lung trainer offers adjustable resistance settings that you set by turning the lower dial. suitable for beginners and athletes, allowing you to easily control the intensity of your breath training. - Safe and hygienic: the mouthpiece is made of food-grade silicone, soft and odorless, gentle on your mouth, teeth, and gums. both the mouthpiece and the vent tube are removable for easy cleaning, ensuring a safe and comfortable experience each time you breathe. - Easy to use: compact and portable, simply bite the mouthpiece, inhale deeply, hold for a few seconds, and exhale slowly. no need to hold the device, so you can use it during daily training or work. - Broad applicability: lightweight and suitable for adults, seniors, athletes, singers, and others who want to improve breathing strength and lung function. may help prevent atelectasis and other postoperative complications. Use scenarios: - during gym workouts or sports practice to warm up or train endurance - for voice work, singing, or public speaking to improve breath control - during daily activities or rehabilitation after surgery to maintain breathing function