A mechanical device intended to simulate/mimic the human lung(s) by imitating its physical properties. This device, commonly known as a test lung, may be a simple ventilation bag filled with foam rubber, or a complicated device, usually mechanical, that can be adjusted to imitate, e.g., change in compliance, airway restrictions, lung perforation. It is intended to be used by a healthcare provider in a clinical setting for the purpose of, e.g., maintenance, testing, user control of a ventilator and for the education of clinical staff.