Looking for a way to add an amplifier to your factory radio? Look no further than the Metra Adjustable Line Output Converter with Volume Knob. This product is designed to work with all vehicle makes and types, and is the perfect solution for anyone looking to upgrade their car's audio system. The Metra WM-LOCKN is an open box 2 channel line output converter that allows for easy installation of an aftermarket amplifier. With its adjustable volume knob, you can fine-tune the output to ensure the perfect sound quality. Don't settle for subpar audio in your vehicle - upgrade today with the Metra Line Output Converter.