This is for one (single) replacement HID Ballast. These are a canbus compatible ballast. These will work with most canbus cars produced before 2008, excluding VAG (VW, Audi, Seat, Skoda etc), BMW, Mercedes, Fiat. These would require a smart canbus system. 

These will work with any traditional HID bulbs on the market as all HID kits use the same plugs. 

If you have tried changing the bulb and it is still not illuminating then chances are you have had a ballast fail.

These are also called a control unit.

Specifications:

• Pack of 1 (single)
• 12v DC
• 35w AC
• Universal HID Fitment
• 12 Month Warranty
• E Marked (Road Legal)
• Direct Replacement
• Single Beam or Bi-Xenon Use
• Temperature Tested