Speakercraft LL-One Line Level A-B Switch Speakercraft LL-One Line Level A-B Switch uses low ohmic relay contacts to provide lossless, distortion-free switching PS-1.0 Power Supply Included Low Ohmic relay contacts provide lossless, distortion-free switching Octal switch provides precision delays from 0.5 seconds to 5 minutes to handle virtually any music energy interval without false switching Sense Level permits adjustment to accommodate a wide range of music level conditions for best switching threshold B Status 3.5mm output jack triggers local devices ( i.e. lighting, etc) where desired Dimensions : L 3 7/16" x W 4 5/8" x H 1" This switch is great for car audio too (for example: auto-switching between satellite radio & iPod) Power supply included View Manual Normally ships in 0-3 business days.