The CWE-MRI-1 Ventilator is a small animal ventilator designed for use in MRI and other high magnetic field environments, though its use is not limited to those environments. Operated alone or controlled/monitored by a computer, the CWE-MRI-1 system consists of a microprocessor-based control unit and a set of remote, pneumatically operated, nonmetallic valves. The CWE-MRI-1 operates on the flow-time principle, dispensing a known airflow into the lungs for a set inspiratory time to generate the desired tidal volumes. The three controls – respiratory rate, inspiratory time and flow rate – allow for accuracy and extraordinary flexibility over a wide range of volumes, breaths-per-minute and inspiration/expiration time (I/E) ratios. An internal air pump generates the respiratory airflow, but CWE-MRI-1can also connect to an external pressurized air or gas source (oxygen or anesthetic gasses). The remote high-speed, miniature pneumatic valves control the airflow switching.