Product Description 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. 4 series sensors can be installed in locations 1 or 2 of the Ventis Pro. (This sensor will not fit or work with Ventis MX4 Series Gas Monitors)Has your O2 sensor failed or has a measuring range that's all over the place? It might be time to replace it. Repair your Industrial Scientific Ventis Pro Multi-Gas monitor by purchasing a new genuine Industrial Scientific Oxygen Sensor.Need some DIY help changing a sensor or just some friendly technical help with repairing your instrument? Call customer service at 1-800-949-7233.