Replacement electrochemical long-life Oxygen sensor for the Ventis® Pro. The O2 sensor has a measuring range of 0-30% by volume with a .1% by volume resolution. The Long life O2 sensor is a biased sensor that requires continuous power to operate to specification, and is powered by the battery in the Ventis Pro. If no power is provided to the sensor it will experience drift and erroneous readings until stabilized. More information on the long-life O2 sensor can be found in the Ventis Pro manual. 4 series sensors can be installed in locations 1 or 2 of the Ventis Pro.