Description: The car power filter will bring you good audio effect. There are 3 wires. The blue wire for input (12V), the red wire for output and the black wire is the ground wire. It is a stable and wear-resistant small noise removal tool. Function: the igniter power supply noise produces a filtration effect, makes the sound effect better. Specification :Material: Plastic, Metal Voltage: 12V Package include: 1pcs Car Noise Filter Isolator Note: Please allow 0.5-1 inch difference due to manual measurement. (1 inch = 2.54cm) Please check the size and picture carefully before payment. Due to the difference between different monitors, the image may not reflect the actual color of the item. Please understand, thank you.