This product is made of optoelectronic transfer technology and is under controlled by micro-computer optical reaction system. Available to induce environment lightness's change then control car's big/small lights turn on or off automatically, replace manual operation to reduce driver's loading and increase security. The fixture run automatically then car's front, behind license plate, dashboard lights turn on while going through tunnel or dark , contrariwise turn off. Original design that check and alarm function when the big light breaking down sometimes