2 RCA/PHONO CAR AUDIO SUBWOOFER CROSSOVER FILTER - NOISE REDUCTION BOX - 3 BAND - - Amazon.com
RCA/phono subwoofer cable, 1 to 1 RCA/phono, digital/analogue - KabelDirekt
Amazon.com: Powered Subwoofer, Bestisan 6.5" Active Home Audio Subwoofer with Bluetooth in Compact Design, Opt/RCA/Bluetooth Input, Built-in Amplifier for Home Theater, Receiver, Speakers, Deep Bass in Black : Everything Else