Kicker 46KISL 2-channel speaker wire adapter (bare-wire connector to RCAs) at Crutchfield
Amazon.com: Scosche LOC2SL Line Output Converter Adjustable Amplifier Add On Module for Car Stereo, 2-Channel Signal Sensing Speaker Wire to RCA Adapter with Remote Control Knob, Black : Electronics
Amazon.com: KICKER 46KISLOC KISLOC 2 Ch Speaker Wire-to-RCA Converter w/ LOC For OEM Radios : Electronics
Speaker Wire To RCA Terminal Adapter For High-Level Signal Connection To Amp - Walmart.com
2 Channel Speaker to Gold RCA Amp Receiver Powered Speakers wire Adapter, 20 Ft. | eBay
Amazon.com: Freajoin 2-Channel High Low Level Converter Speaker Cable to RCA Adapter with Remote Output : Electronics