H4 bulbs are commonly used in domestic and import vehicles in as a single headlight bulb capable of high and low beam. H4 bulb are usually held in place with a simple wire clip, making them super easy to upgrade to LED. HVC offers many different H4 LED kits in various lumen outputs to satisfy all budgets and light output desires. All kits are plug-n-play and require minimum effort to install. 8G, X7, GT, and X9 are the four brightest H4 LED kits. If you need canbus compatibility then X7 will be your best choice.