Product Description Replacement electrochemical Phosphine sensor for the Ventis® Pro. The PH3 sensor has a measuring range of 0-10ppm with a .01ppm resolution. This 6 series sensor is only available in the Ventis Pro 5, and can be installed in locations 3 or 4 (This sensor will not fit or work with Ventis MX4 Series or Ventis Pro 4 Gas Monitors)Has your PH3 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 (PH3) Phosphine 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.