Description Remark: This listing is up for a pair of D2C light bulbs. A D2C bulb is a bulb that has notches in the base to fit both D2R or D2S housings. Nearly all vehicles that come with an HID system from the factory use either a D2R or a D2S bulb. This is the most common type of HID bulb used by car manufacturers. D2C bulbs can be used with any vehicle that uses either a D2R or D2S bulb because the base fits both of these head light housings. Please refer to the picture. FAQ: Q. Would D2C light bulb fits my D2S/D2R socket? A. Yes . D2C bulb is a bulb that has notches in the base to fit both D2R or D2S housings. If you receive D2C light bulbs, just try it on the D2S/D2R socket and they should fit perfectly!