Most likely all European vehicles will need a Canbus , this option is to purchase as separate, Series X-Apollo X-Aurora X-Warrior X-T1Pro already come with Decoder. Some newer American vehicles might need an extra decoder when using X-Apollo X-Aurora X-Warrior X-T1Pro Voltage: DC 12V-14V Cable Length: Approx. 30cm Usage: Headlight, fog light 95% Error free Bulb Size: H4, H13, 9004, 9007,High Low BeamH1, H3, H7, H11, (9005, 9006, 9012 same), 5202, 880/881 (Single Beam) The decoder can solve the following problems: The indicator of the instrument panel lights when the headlight is used as Fault Light. The indicator of the instrument panel doesn't light when the headlight is used as High Beam. The LED headlights flash when starting the engine. The engine stops working when turning on the LED headlights. Error warning: LED headlight doesn't work LED headlight keeps flashing after installation. One of the LED headlights work, but the other one doesn't work. LED headlights automatically turn off after lighting up for a few minutes. X-Decoder Series LED Headlight Bulbs Canbus Driver *2