Pack of 8 replacement mouthpieces for use with a manual spirometry lung volume kit (LNGKIT) Used to study the volume of gas in the lungs during the respiratory cycle, an integral part of pulmonary function tests Great for studying the various factors that can change a person's lung capacity, including old age, diaphragm weakness, and loss of elasticity Average lung capacity is approximately 6 liters, although volumes will vary depending on the depth of respiration, ethnicity, gender, age, body composition, and in the presence of certain respiratory diseases Mouthpieces can be washed and disinfected - For educational or demonstration use only - Do NOT use to diagnose any medical condition