Garfour Service: Our human customer service is available 24 hours a day. If you encounter installation and product problems, you can communicate at any time!. Product accessories: 1 set of products (1*iron plate) (1*color voltmeter) (1*cigarette lighter base) (1*wire set) (5*installation screws). How to use: The first step is to use the red and black interface to connect the positive and negative poles (red positive pole, black negative pole) on the back of the product. Plug in the power at the other end of the line and use it right away!. Product function: The base can light cigarettes, charge and so on. The color voltmeter can know the current wiring voltage in time. Can be installed on cars, RVs, boats, etc. Product features: Dustproof and waterproof (splash water) color voltmeter + car charger base. The base can be used with any circular socket device you use. The voltmeter is better looking and easier to tell the voltage situation. Comes with a small fuse box.