Our Diesel Emissions Fluid Filler Cap prevents diesel exhaust fluid from leaking through the filler neck. Integral for keeping pollutants out of the environment, replacement restores fluid system. Product Features:A necessary replacement item for passing inspection in certain statesConstructed from high- quality, heat-resistant materials for a long service lifeDirect replacement for a proper fitVehicle try-on testing and vibration testing have been conducted on this part to ensure trouble-free performance