Reality Check: Customers often ask, Do I really need a harness? Yes! A relay harness is designed to deliver steady voltage to your HID ballasts directly from the car battery. Nobody likes a flickering headlight, so why risk it? Factory headlight outputs are really only designed to power a halogen light bub, not an HID ballast. Under Control: GTR Lighting makes it easy with the H4 Bi-xenon relay harness. Designed to be completely plug-n-play; it's a seamless solution to keep your low and high beams under control with the original stalk inside the car. Works perfectly with Bi-xenon projector retrofits and Hi/Lo HID systems. Advanced: The third generation 8-Pin Relay has a tiny built-in capacitor that stores and releases it's charge between mode changes. So even if there's a short gap between the low and high beam signals from your car, your HID's will run smoothly. It's sealed weather-pack connector is new for 2014 and is a major reliability upgrade compared to other bi-xenon harnesses. Universal: This harness is designed to work with both positive and ground switched headlight circuits, making it universally compatible with all vehicles no matter new or old. Plug n Play: The layout of the harness makes it easy to install. With just a few simple connections, even your mom could set this thing up! Wire lengths are long enough to be used in everything from compact cars to SUVs and it's designed to be 100% plug and play (no cutting or splicing needed). OEM Grade: Aside from being ahead of the game from a technical standpoint, this harness is also a work of art. With it's wiring protected by abrasion resistant Techflex mesh sleeving and it's extruded aluminum relay shell that's been anodized and laser engraved - the GTR Lighting Bi-Xenon Harness will look factory fresh under the hood!