?Reliable and Friendly Service?Ready to respond within a 24 hour time frame. 30-Day money back guarantee, 12 month replacement and lifetime Support. ?Max Compatibility? Professional power filter for most of DC 12V devices. Effectively resolve the noise problem of car audio. Compatible with car stereos receivers, equalizers, amplifiers, speakers, etc. ?How to connect?The red wire connects to the battery 12v+, the yellow wire connects to the power cable of the stereo where the electricity is going. The black wire connects to the vehicle’s metal frame or any available ground wire. ?Reduce Audio Noises? Filtering the power supply can reduce noise generated by the cigarette lighter or the other electronics. Get crystal clear sounds from the car speakers. ?Car power filter?It can eliminate the EMI/Ground Loop interference in the power source caused by the other car electronics or ignition. Especially good for car audio, sensitive electronic equipment, etc. Size: 2.5 x 1.7 x 0.1 inch. Wiring Length:7.5 inch.