This new Racor Fuel Drain & Sensor RK42043 fits the stock OEM fuel filter also made by Racor. It also fits aftermarket filters. Racor is the OEM supplier for AC Delco. This sensor is the stock item on Duramax powered vehicles. We sell the OEM Duramax fuel filter p/n PFF50216 as well. The sensor is manufactured by Racor here in the USA and is the stock OEM sensor on the new Duramax vehicles. Sensor fits all GMC and Chevrolet Duramax 6.6L diesel engine vehicles from 2001 through 2015. We have hundreds of these sensors in stock and ready to ship.