For xenon bulbs, the most likely thing to break is the ballast. The color temperature of the light bulb is either 4300K ??or 6000K. If it is higher, don’t install it because it is too blue. (The xenon lamps of original cars use 4300K.) Domestic ballasts are mainly Mingdu and Aquamarine. Better ones include imported Koito, Valeo, Panasonic, etc. Philips seems to have them too. Bifocal lenses: mainly Hella 2nd generation, 3rd generation, Koito Q5 lenses, etc. The domestic Hella 2nd generation lens I use is very good and cheap. The low beam tangent is perfect and the high beam is powerful! 2. Nowadays no one will pretend to be both near and far. There is a better solution, which is to only change the low beam, and add a bifocal lens in front, that is, there is a light shield. In the low beam state, the light shield blocks part of the upper light, and there is an obvious tangent line in the light. After turning on the high beam, the sunshade opens to realize the high beam. At the same time, with the original car's high beam, four high beams will be realized, which is extremely powerful!