This is a high quality Philips Xenstart 4300k D1R equivalent. It is a clever combination of an OEM 4300K Philips HID D2R bulb and an aftermarket igniter box that gives you versatility and long term cash savings. The igniter is equivalent to the Philips Xenstart box found on D1R bulbs. It can be used with any D2 bulb to create the D1 equivalent!! This give you much more choice in replacement bulb. For example, in the future you my decide to fit a Philips 6000k D2R to the D1 base to make a 6000k D1R with all the Philips quality! D2 bulbs have a much wider selection than D1 bulbs and are much cheaper. On top of that why buy the whole D1S unit (bulb and base) each time when you really only need to replace half of the component? Now you can choose to replace either the bulb or the base! In the long run you will definitely save money through this component. Each time your bulb runs out you can simply purchase a D2R and save £££. This is a bulb+base price. If you just want the base alone CLICK HERE .For other questions regarding application, Wholesale or other queries please don't hesitate to contact HIDorigin@gmail.com