The American International S-25A noise filter helps eliminate noise that comes in through the 12-volt power line on your in-dash receiver or signal processor. Installation is simple. You have three wires to connect: one to the power line from the battery, one to the receiver's power line, and one to ground. The S-25A noise filter is recommended for audio components rated up to a total of 25 amps and 350 watts. Mounting hardware is included. Warranty: 30 days.