Describe:This LED alarm does not require a car alarm system.No wires are needed, just stick it on the roof of the car with the corresponding glue.Solar energy can be absorbed and stored in high-efficiency solar cells.You do not need to install batteries. It is powered by solar energy.I have tested it myself and the LED can flash all night when there is enough sunlight during the day.You don't need to put it directly in the sun. The sunlight above the dashboard is sufficient.No matter you put the switch on or off, it can be charged by solar energy.Size: 5*2.5cm (2*1 inches)The switch is small. You need a ballpoint pen or small stick to push it. Color: blue, red (please note the choice, otherwise it will be shipped randomly)The package includes:1 x warning light