The Rolls DB228 Wall Direct Interface is a passive transformer-isolated direct box, which mixes an XLR microphone input with an unbalanced 1/8" stereo input to a screw-terminal pluggable strip. The interface is ideal for impedance matching any consumer-level audio signal such as CD, DVD, and MP3 players to a professional audio system. The Rolls DB228 offers a level control and will pass phantom power. The Rolls DB228 can be mounted into an optional electrical wall box, while an optional standard Decor'a wall plate is available for a clean and finished look.