A: the HID headlights xenon lamp waterproof cap installation is divided into two: one is the original lamp power cord in the fixture, when the installation of such models leads to be sure the power cord from the tarpaulin, and the headlight lamps and rear cover expansion hole device punch. The diameter of the reamer is generally 25MM, as early as the operation should be waterproof cap diameter prevail. Another power cord of the original lights in the lamps outside, most of the 900 series bulbs so, the installation of such models more directly connect the power supply and ballast (or line signal line group) can be and waterproof hat and lighting consistent with the phase.