Product description Lung demonstration kit The kit includes a transparent plastic container, y-tube "trachea", balloon "lungs". Allow students to build a demonstration model of a human lung and learn the basic concepts of respiratory physiology During the demonstration, the pull of the hand under the diaphragm can be pulled When the pulmonary gas is demonstrated, the interaction between the lung and the diaphragm is the downward movement of the diaphragm and the lung becomes larger When demonstrating an exhalation, the lung and the diaphragm move up and the lungs become smaller Model size :21*11cm/8.2*4.3inch Materisl: PVC plastic+rubber