FLOW RATE INDICATOR: Use the indicator for guidance. If the indicator rises above the upper level, you are inhaling too quickly. If the indicator stays below the lower setting, you are inhaling too slowly. The goal is to keep the indicator in the middle position. This means you stay smooth and in control. HIGH-QUALITY MATERIAL: The deep breathing trainer is made of high quality break-resistant plastic, no peculiar smell, Compact, measurement and deep breathing training system. EASY TO USE: Integrated molding,The breathing exercise device has a built-in filter cotton, which makes your cleaner.5000ml Volume Measurement with Flow Rate Indicator,Removable for thorough cleaning and hygienic maintenance. INSIST ON USING: Breathing exercise for 5-10 minutes every day, and keep on exercising to get better effect. EASY TO CLEAN: The tube and mouthpiece are easy to disassemble for cleaning, and the stable bottom is more durable,After use, keep the device clean by placing it in a ventilated and dry place.