The Monoprice SS-Pro 12 is a powerful and efficient dual source, audiophile grade speaker selector for up to 12 pairs of speakers. Featuring robust transformers, the SS-Pro 12 allows you to play all 12 pairs of speakers at once without damaging the amplifier, and is able to withstand up to 300 watts peak of power per channel. A front panel A/B switch allows you to choose between two amplifier sources, and easily removeable snap in connectors make installation easy. A rotary switch located on the rear panel can be used to set the appropriate impedance based on the number of pair of speakers connected. 12-zone speaker selector that allows you to connect up to 12 pairs of speakers or 12 listening zones and control each zone with front panel push-buttonsUtilizes audiophile-grade impedance-matching transformers to safely distribute maximum power throughout your systemEasy to use front panel switch to choose between sourcesDesigned for use with either 4 ohm or 8 ohm speakersProtection circuit ensures your amplifier is protected Warning: This product can expose you to Phthalates, which is known to the State of California to cause cancer and reproductive harm. For more information, go to www.P65Warnings.ca.gov