Planet Audio Surround Sound Car Subwoofers, Black, 8.86 x 12.20 x 2.95 Inches, 10.25 lb

Built-in Amplifier – Low-Profile Subwoofers that are amplified do not need an external source and are generally very compact Mosfet Power Supply – 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 & Low Level Inputs – A low level (RCA) input is measured in voltages. A high level (+/- wire) input is measured in wattages. Both essentially carry signal from your receiver to your amplifier to your speakers Variable Bass Boost – Variable Bass Boost allows you to adjust the low bass within the boost range to just the way you like it