Product Description Replacement catalytic bead combustible LEL Pentane sensor for the Ventis® Pro. The LEL pentane sensor has a measuring range of 0-100% LEL with a 1% LEL resolution. This sensor is calibrated with pentane but can detect a wide variety of combustible gasses. 4 series LEL sensors can only be installed in location 2. (This sensor will not fit or work with Ventis MX4 Series Gas Monitors)Has your LEL 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 LEL 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.