Twice the size of a human adult heart to show detail and facilitate study. This simplified reproduction is perfect for introductory study. A 7-page study guide explains the physiological function of each the 39 features number-coded on the model. 100% American Made - authentic hand-painted detail is proudly signed and dated by its crafter. Three hinged portals allow full access to heart chambers and valves. Attached portions of trachea and esophagus demonstrate their relationship to major vessels. Unbreakable vinyl model fully rotates on wooden pedestal, or lifts off for pass-around viewing. Overall dimensions on base: 7x7x15 inches (18x18x38 cm).