This assembly features a high-grade filter element that can trap contaminants as small as 2 microns. It includes an integrated water sensor that alerts the driver if water is detected in the fuel system. Clean fuel is critical for the longevity of expensive diesel injectors and high-pressure pumps. The housing is built to withstand high fuel pressures without leaking. Regular replacement of this assembly is the best insurance against costly diesel engine repairs caused by contaminated fuel.