Purpose: The sensor alerts the Engine Control Unit (ECU) and/or dashboard warning light to indicate the presence of water in the vehicle's fuel system. Compatibility: Suitable for 2001-2011 Silverado Sierra 2500 HD & 3500 HD Duramax d-iesel models, including the 2007 Classic versions with the 6.6L Duramax engine. Specifically designed for the fuel filter and water-in-fuel sensor. OEM Replacement Details: This Duramax water-in-fuel indicator sensor matches the specifications for 2001-2011 6.6L Duramax engines (LB7, LLY, LBZ, LMM, LML). It serves as a direct replacement for OEM part numbers 12639277, 12639450, 97384931, and 97261720, and is compatible with fuel filters including TP3018, 12664429, 12646512, among others listed. Installation: Effortless installation is achieved through a direct fit at the base of the Duramax fuel filter, utilizing the factory-specific wrench provided for seamless attachment. Contents: The package contains one Duramax fuel filter water-in-fuel indicator sensor equipped with an O-ring. MOXRUQ Car Water in Fuel Indicator Sensor, 6.6L V8 Duramax Engine Fuel Filter Sensor Replacement OEM #12639277, Compatible with 2001-2011 Silveardo Sierra Truck 2500 2500HD 3500 3500HD (Black)