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-buttons Utilizes audiophile-grade impedance-matching transformers to safely distribute maximum power throughout your system Easy to use front panel switch to choose between sources Designed for use with either 4 ohm or 8 ohm speakers Protection circuit ensures your amplifier is protected