How does spirometer look like?

A spirometer is a device used to measure the volume of air inhaled and exhaled by the lungs. It typically consists of a cylindrical chamber or tube that can be filled with air, often with a digital display or dial to show measurements. Some spirometers have a mouthpiece for the user to breathe into, while others may involve a bellows or water displacement mechanism. The design can vary, but they generally have a compact and portable form for easy use in clinical settings or at home.