Walker Products MAF sensors are always 100% NEW and NEVER remanufactured! All sensors are 100% programmed and tested for fit, form, and function before being available to be sold. As an industry leading program, Walker Products manufacturers high demand SKUs in our USA facilities with OEM quality components, custom engineered circuit boards, and programing. Many of the Walker MAF parts are designed and built here in the USA at Walker Products facilities. The Walker Mass Air Flow Sensor program offers replacement sensors in both Sensor Only and Complete Sensor and Housing Assemblies. Sensor only replacement is typically faster and more economical, but some manufacturers recommend that you replace the complete housing assembly to ensure the connector air tubes are clean and to protect the sensor itself, which can be damaged by oils on your hands or even air pollution. Walker Products Mass Airflow Sensors stand apart from the competition due to the focus on ensuring customers receive the best product possible. The most popular applications are made entirely in the United States which allows for the highest quality sensors. When it comes to MAFs, it is vital that they are properly tuned to the vehicle, which is why Walker's team of engineers work to create sensors that have custom tuned flow characteristics for the full flow spectrum. Walker MAFs continue to meet or exceed OE long-term fuel trim percentages, and calibrations go through 100% production testing and are always verified using on vehicle testing. Walker Products provides our customers with the confidence that they are investing in nothing short of the best. Walker Products began supplying the fuel system needs of the automotive industry in 1946. Today, Walker is an ISO 9001/ IATF16949 certified manufacturer, and one of the largest privately owned manufacturers of fuel system components and engine sensors.