Human lungs, working model

Model of how the human lung works. Expansion of the lung by enlargment of the chest cavity. In the bell-shaped model two balloons are filled resp. emptied by moving a membrane which represents the diaphragm. Very practical for demonstrating how the human lung works Easy to use, simple design The model consists of a transparent bell with a height of 30 cm, a holder for two ballons and a durable membrane.