Use the RF-HLC4 high-to-low signal converter to connect 4-channel amplifiers to radios without RCA outputs. The RF-HLC4 is a 4-channel high-level to low-level signal converter designed for factory or aftermarket radios that do not have dedicated low-level RCA outputs. The adapter converts high-level signal from the radio^s speaker line and transforms it into a safer low-level audio signal. This allows you to add a 4-channel amplifier to your system for higher power output and better sound quality.