This applies only to the inner diameter of the atomizer and an inner diameter 16MM 12MM cartridge hose. Please keep the nebulizer upright (trachea interfaces facing down) when you install and use.Before using the record bubbler water poured into 4/5.,Start using refiner piece big bubble will emerge is a normal phenomenon, after 24 hours of continuous use big bubble gradually reduced, up to 3 days after the big bubbles disappear. Size:12cm x 6.5cm x 2.5cm.