Mounting in the bottom of the fuel filter, the sensor detects water in the fuel. Fuel Sensor Part Number: 3808616, 874572 Compatible Models: D3, D4, D6 Replaces Part Numbers: 3808616, 21139810 Compatible with Crude Oil Systems: D3-110I-A, D3-110I-B, D3-110I-C, D3-110I-D, D3-110I-E, D3-130A-A, D3-130A-B, D3-130A-C, D3-130I-A, D3-130I-B, D3-130I-C, D3-140A-D, D3-140A-E, D3-150I-D, D3-150I-E, D3-160A-A, D3-160A-B, D3-160A-C, D3-160I-A, D3-160I-B, D3-160I-C, D3-170A-D, D3-170A-E, D3-170I-D, D3-170I-E, D3-190A-B, D3-190A-C, D3-190I-A, D3-190I-B, D3-190I-C, D3-200A-D, D3-200A-E, D3-200I-D, D3-200I-E, D3-220A-D, D3-220A-E, D3-220I-D, D3-220I-E, D4-180I-B, D4-180I-C, D4-180I-D, D4-180I-E, D4-210A-A, D4-210A-B, D4-210I-A, D4-210I-B, D4-225A-B, D4-225A-C, D4-225A-D, D4-225A-E, D4-225I-B, D4-225I-C, D4-225I-D, D4-225I-E, D4-260A-A, D4-260A-B, D4-260A-C, D4-260A-D, D4-260A-E, D4-260D-B, D4-260D-C, D4-260D-D, D4-260D-E, D4-260I-A, D4-260I-B, D4-260I-C, D4-260I-D, D4-260I-E, D4-300A-A, D4-300A-C, D4-300A-D, D4-300A-E, D4-300D-A, D4-300D-C, D4-300D-D, D4-300D-E, D4-300I-A, D4-300I-C, D4-300I-D, D4-300I-E Material: Plastic Color: Black Package Contents: 1 x Water Sensor Note: Only the items listed above are included. Other products are not included. Light reflection and differences in display settings may cause slight variations in the color of the item as shown in the picture compared to the actual product. Measurement may vary by +/- 1-3 cm.