BOSS Audio AR4000D Armor 4000 Watt, 1, 2, 4 Ohm Stable Class D Monoblock Car Amplifier with Remote Subwoofer Control POWER: 4000 Watts Max x 1 @1-Ohm, 2000 Watts Max x 1 @2-Ohms CLASS D: Power loss is significantly reduced making the amplifier highly efficient. Excess energy is stored until its needed instead of being converted into heat. Reduction in size/weight, reduced power waste, smaller heat sink, compact circuitry 1 OHM STABLE: Able to continuously power loads of 1 Ohm without encountering difficulties such as overheating. Typically made to power up subwoofers that demand the heavier power load requirements to be able to perform the way they were made to STRAPPING CAPABLE: You are able to strap TWO AR4000D amplifiers and double the power that is being sent to your subwoofer(s). You now have the ability to connect more subwoofers to take advantage of the extra power VARIABLE SUBSONIC FILTER: To prevent your subwoofer(s) from bottoming out, the variable subsonic filter filters out frequencies below the subwoofer(s) specified low frequency limits and allows the driver to reach a maximum safe excursion VARIABLE LOW-PASS CROSSOVER: Subwoofers reproduce sound based on a number of different low-range frequencies. You can set exact sound specifications for the bass frequency reproduction DIMENSIONS: The AR4000D is 14.3 inches in Depth, 6.5 inches in Width and 2.8 inches in Height WARRANTY: BOSS Audio Systems provides a powerful 6 year Platinum Online Dealer Warranty so long as the purchase is made through Amazon.Com