Sound Storm Laboratories US10K 10 Inch Powered Under Seat Car Subwoofer - 1000 Watts Max, Dual 4 Ohm Voice Coil, 8 Gauge Amp Installation Kit Built-in Amplifier - Pulse Width Modulated design simplifies power supplies. It controls the output voltage and current precisely by removing the output current sensing loss & eliminating all secondary feedback circuitry. It’s efficient & reliable KIT – 17’/8G red power cable, 40 amp fuse holder, 3’/8G ground cable, 16’/18G blue remote cable, 16’ RCA interconnect, 4" wire ties, plastic grommets, #10 gold-plated ring terminals, butt splice wire connectors, tap screw, rubber terminal boot 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 US10K 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 US10K with the source unit. Most aftermarket radios have multiple pairs of RCA outputs that can connect to multiple amplifiers