[Replace Part Number ]A2189009203, A2189009700, A1668203689 [Fit The Following Models]suitable for W166 X166 C218 X218 R231 ML SL [HID headlight ballast replacement]Headlight Control Unit, a crucial part of HID lighting system, 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. Every ballast is designed to connect directly to your vehicle and requires NO programming or coding. [Premium quality ]made of premium aluminum suitable for better heat dissipation and vibration resistance,6 protections against overpressure,low pressure,overheating,no-load,short circuit,reverse connection suitable for more safety and durability [Fast startup & safe stability]built-in high pressure bag can current conduction speed & save power consumption suitable for fast startup,also can protect high pressure bag from any dust & rain in the engine environment to enhance security Specification: Power: 35W Beam angle: 360' Waterproof rate: IP 68 Operation voltage:DC 12V Working temp: -40 Celsius, +80 Celsius Shell meterial: aviation aluminum Part Number:A2189009203,A 218 900 92 03,2189009203 A2189009700,A 218 900 97 00,2189009700 A1668203689,A 166 820 36 89,1668203689 Fit suitable for Vehicle Models: ML-Class W166 2011-2015 -Class X166 2012-2015 -Class C218, X218 2011-2015 SL-Class R231 2013-2016 Colour:Black + Silver Material:metal Package Contents: 1* Headlight Ballast Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.