Cheap Car Audio Best Amp for Speakers 4 Channel Boss 400 Watt Amplifier Black 400 W MAX Power, 4 Channel 75 W X 4 RMS @ 2 ohm 38 W X 4 RMS @ 4 ohmFull Range, Class AB,High and Low Level InputsPower Input Terminals When installing all Boss Audio Systems amplifiers, it is important to use the maximum gauge of wire that the power terminals will accommodate. For instance, if an amplifier has 4 gauge power and ground terminals, use high quality 4 gauge multi-strand copper wire to make your power connections. This maximizes the amplifier’s ability to draw the required power upon demand. This also helps prevent overheating that could cause failure. Always make sure your vehicle’s electrical system is capable of handling the current demands from any after-market accessory.Please refer to the amplifier’s owner’s manual for correct wire gauge sizes.Fuses Fuses protect both the amplifier and the electrical system of your vehicle from faulty conditions.If you must replace a fuse on the amplifier, always use a fuse of exactly the same type and rating of the one you are replacing. A different type of fuse or rating may result in damage or cause a fire. Please refer to your owner’s manual for reference on fuse size and type.If you plan on using multiple amplifiers in your system, be certain that you have the appropriate sized gauge wire to accommodate the current demands for all amplifiers and that the wire is fused correctly at the battery. Connect an empty fuse holder within 18 inch (45 cm) of the car battery and run a 4 gauge (or heavier) cable from this fuse to the amplifier location. A fused distribution block is recommended when using several amplifiers or accessories.Proper Grounding Proper grounding is essential for any electric accessory in a vehicle.Some key points to remember: Keep the ground as short as possible. Connect the amplifier’s power ground terminal to the closest point on the chassis of the car. Keep this ground wire to less than 39 inch (100 cm) in length. Use 4 gauge (or heavier) wire. Scrape any paint away, use a star washer to bite into the metal and secure it tightly using a grounding lug.Any steps that aren’t followed properly will result in a higher resistance at the ground point, causing unnecessary heat, high current draw, and potentially damaging the electrical accessories in the vehicle.Installation Please be advised that Professional installation of all of our products is recommended and encouraged. Installation by a professional installer increases the length of any applicable warranty on most Boss Audio Systems products. The warranty is void, however, on product that is damaged during installation by a non-professional installer. Professional installation should also ensure trouble-free usage for years to come.Cheap Car Audio Best Amp for Speakers 4 Channel Boss 400 Watt Amplifier Black I ship to the lower 48 states. I cannot combine shipping. No local pickup. I cannot ship to military addresses.