Nasco Heart Model is a two-piece model which opens in half to show the inner chambers and valves of the heart. Also visible are the aortic arch, superior and inferior vena cava, and pulmonary and cardiac veins. The Nasco Heart Model comes mounted on a stand and includes an information card. 3-3/4" x 4" x 4-1/4". Card size 6-1/2" x 5-1/4".