Some models of car will output voltage interference after the engine is started. The power supply to the reversing light is not pure DC power supply, but a pulse signal is superimposed on tops oscilloscope can be used to test if the conditions will it found a similar squarewave signal. The camera power supply line directly on the reversing light, and the host can see there is a severe interference, or not to reversing screen. Features -Color: Multicolor -Material:Plastic -Size:17.00X1.50X1.50cm/6.68X0.59X0.59in -Voltage: 12V -Installation: Black Wire: Negative; Red Wire: Reversing Light Positive; Blue Wire: Camera Positive - Car Camera Filter Cable is manufactured with professional technology to ensure the stable usage of the product and can work for a long time. - Easy solution to your troubles. Provide you with more considerate design and service. - Designed for auto car rearview camera and use to the car rearview camera problem like "black screen". - Made of plastic material, it is durable, strong and practical with longer service life. - It is in stable characteristics, high performance and it is in great reliability, simple, easy to install. Package List4 x Car Camera Filter Cable