Plug-N-Play: Forget about crimp-on wire taps, these convenient "Y" pigtails make splitting or doubling the signals from your headlight system easy and clean. Double High Beams: So you already have a halogen high beam? When retrofitting a bi-xenon projector; you can harness the stock high beam power to activate the bi-xenon solenoid at the same time, thus doubling your high beam output. Quad Retrofits: Use a splitter to run two low beam harnesses in parallel for four ballasts and then activate two pairs of bi-xenon solenoids off a single high beam output. Three total splitters needed. Sport Bikes Retrofits: Instead of a single low beam and a single high beam, you can retrofit two bi-xenon projectors and split the single high beam output into both projector solenoids. Instant dual low beam dual high beam setup! (generally H7 Male to 9006/9006 female) All Fitments: For the input, make sure to select the size that matches with your stock high beam bulb type. The output will generally be the female version of that same bulb, coupled with a 9006 to plug into your bi-xenon projector solenoid.