BUILT-IN AMPLIFIER: With a MOSFET power supply you get improved switching speeds, better performance with less power from the driver, lower gate-to-drain feedback capacitance, lower thermal impedance for higher switching frequencies VARIABLE LOW-PASS FILTER: A low-pass filter is an electronic circuit that removes all the notes below the filter's frequency setting. You will use the Low-pass filter to primarily keep high notes out of your subwoofer(s) HIGH LEVEL INPUTS: Speaker level inputs are commonly referred to as high-level inputs. It will be used to connect the LOPRO8 to your factory radio or an aftermarket radio that does not have low-level (RCA) inputs LOW LEVEL INPUTS: Line level inputs, also known as RCA inputs or low-level inputs, use RCA interconnect cables to link the LOPRO8 with the source unit. Most aftermarket radios have multiple pairs of RCA outputs that can connect to multiple amplifiers VARIABLE BASS BOOST: Variable Bass Boost allows you to adjust the low bass within the boost range to just the way you like it DIMENSIONS: 15” x 9.75” x 3”. If you are short on space, this is a great solution for you. The combination of amplifier and subwoofer all into one, makes this ideal for spatially challenged vehicles WARRANTY: Sound Storm provides a Powerful 3 Year Platinum Online Dealer Warranty so long as the purchase is made through Amazon.com. We strongly encourage professional installation of this product to ensure proper and safe functionality