HID Kit Canceller Plugs Capacitors for Stability of HID Conversion Kits (Pack of 2) Designed to work with Single Beam HID kits such as 9006 9005 H11 H1 H7 etc Works by plugging into your ballast; while other end goes to the wire that feeds power from your vehicles factory harness Reduces and filters noise on the system Works Single beam HID kits only ; Will not work on Bi-xenon (High/Low kits with relays) Pack of 2; May work with BMW/Euro Vehicles with flickering issue