1.Reference OE part number: 208479-00, ST5872H, H1BB-13D278-AC.Product name: Headlight Ballast Unit Assembly 2.Function: this headlight control unit provides the voltage needed to start the lamp and regulates the electrical current of the light once it is lit. A failed ballast will cause your bulb to burn. 3.High performance: this headlight ballast is designed to meet or exceed standards of factory headlight ballast. Exact fit for plug-and-play. Manufactured from quality material, high strength and durability, which has a long service life. 4.Easy installation: this headlight ballast is engineered to stringent OE specifications, it is sure to exact installation and function the same or even better than the part. 7.Compatible for ford Fiesta MK8 Titanium Hatchback Compatible for ford Fiesta MK8 1.1 Ti-VCT 2017-2021 Compatible for ford Fiesta MK7 VII HJ HF