Compatible with A8 S8 A8L 2010 2011 2012 2013 2014 ; for Q5 2009 2010 2011 2012 2013 2014 2015 2016 2017 Material: Our ballast has good durability and heat resistance, works stably, is not easily damaged by collision, has large cold start current, will not over-voltage, accelerates the bulb without overcharging, and extends the use time of the bulb; Function: The headlight ballast has five powerful protection functions: short circuit protection, open circuit protection, polarity protection, overload protection and load protection to ensure driving comfort. Quality: Made of materials that meet strict OEM requirements, this product offers stable performance and is an ideal replacement option. Note: To ensure you receive the correct item, please confirm that your OEM number matches the one in the description.