electroluminescent delivery driver car light sign, for indoor use , car sticker , can be used for lateral and rear window of your car, with suckers that can be adhere to the windows of your car and can be quickly removed when you are not delivering. Easy On and Off by power inverter with three steps switch to turn on, off and blinking lihgt, which connects by USB to the USB ports on your car s dashboard. Silicone SUCKERS only stick to the flat surface of the windshield or windows. If it rests on a line or irregular area such as wallpaper, stickers or lines, it will not set well. The USB inverter makes a low - sound when it turns on, which is normal for its operation. This low -ACUTE sound may be a little more intense if you turn on the inverter without having the sticker connected. So always keep your sticker connected to the inverter. During the day in cars with dark tinted windows the stickers are not visible. In this tinted glass the stickers will only be seen at night