[Replace Part Number ]A2189009203, A2189009700, A1668203689 [Fit The Following Models]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 for better heat dissipation and vibration resistance,6 protections against overpressure,low pressure,overheating,no-load,short circuit,reverse connection for more safety and durability [Fast startup and safe stability]built-in high pressure bag can current conduction speed and save power consumption for fast startup,also can protect high pressure bag from any dust and 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, and80 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 For Vehicle Models: ML-Class W166 2011-2015 -Class X166 2012-2015 -Class C218, X218 2011-2015 SL-Class R231 2013-2016 Colour:Black and Silver Material:metal Package Contents: 1x 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.