Laptop sound port is compact adapter that plugs into laptop computer speaker jack, changes output to balanced mic-level signals and mates with standard XLR audio cables for connections to house audio system. Ground lift switch assures hum-free interface. On-board volume control. This is stereo version of LSP-1. Separate volume controls for each channel and sum switch to combine them into one mono signal. Includes alternative USB sound capture from computer for clearer signal. No drivers required for Windows 7 and XP. Stereo headphone monitor loop-through and output mute switch. USB mini cable and carry pouch.