EWK Water Sensor Wrench For 6.6L GM Duramax Diesel Fuel Filter 2012 + UP 1. Hexagon. 2. For use when replacing the fuel filter or when servicing the water sensor. 3. The plastic sensor is easily damaged by tools that do not specifically fit the sensor. 4. Application Model / Year : 2012 and Newer 6.6L Duramax diesel engines (OEM version)