boss audio ava1210 7 band pre-amp equalizer with remote subwoofer level control - Walmart.com
Amazon.com: Parametric Equalizer with Subwoofer - 9 Volt RMS Pre-Amp Output with Subwoofer Gain Control and 2 Input Sources Selectable, Pre-amp Line Aux Inputs Via RCA Jacks : Electronics
Planet Audio PEQ10 4 Band Half Din Pre-Amp Equalizer w/ Remote Subwoofer Control 636210300021 | eBay
Amazon.com: PyleUsa 7 Bands Graphic Equalizer with SUB Volume Adjustable for Subwoofer Channel, Built in Bluetooth for Wireless Music Streaming, Stereo RCA Output, Aux RCA Input, Mounting Hardware Included : Electronics
4 Band Pre-Amp Half-DIN Car Equalizer, Subwoofer Output, Dual Color Illumination - Walmart.com
Amazon.com: LANZAR Parametric Equalizer Subwoofer - Gain Control & Bluetooth Wireless Audio Connectivity Blue Light Illumination, Version: 4.0, Range: Up to 32 ft Simple Pairing, Black (HTG50EBTH) : Everything Else
AUDIOPIPE EQ-4-V15 4-BAND CAR AUDIO GRAPHIC EQUALIZER EQ W/ SUBWOOFER CONTROL – LifeAfterBass
5 Band Parametric Equalizer & Pre-Amp Subwoofer Gain Control - Amplifier - Audio Accessories