he Laptop SoundPort^TM(Model LSP-1) is a compact adapter that plugs into a laptop computer speaker jack, changes the output to a balanced mono mic-level signal and mates with standard XLR audio cable for connections to a house audio system. A ground lift switch assures a hum-free interface. On-board volume control. Dimensions: 3.25" x 1.25" x 1" Weight: 6 oz