Was told that this would do both headlights and taillights. That is INCORRECT. When I received box it specifically said "headlight wig-wag flashing system". Other than that, it works great. You have to cut the headlight wires but just follow the diagram and you'll be fine. I was nervous so I called the customer service number. They told me exactly what to do without making me feel like an idiot. Wire connectors, electrical tape, and extra length of 14 gauge wire would all be helpful as the power wire they give you is only like 18 inches long - which makes it hard to wire up to your battery. I purchased extra wire at Lowe's for like $7.00 or something.