This harness is designed to upgrade most American cars with a 4-headlight system to H-4 style halogen bulbs. Also provides your quad H-4 headlight system with consistent battery voltage. Amperage is sourced directly from the battery instead of the headlight switch, which results in brighter headlight beams. Kit can also be used to relocate head lamps to a remote location. This kit includes: Two 40-amp weatherproof relays, two weatherproof relay bases with harness, mating connectors to factory headlights and harness & mounting hardware.