Xantech XSS24100W Two Source Four Zone Speaker Selector (Discontinued by Manufacturer) Product Information-Compatible Devices-Speaker, Amplifier, Receiver:Product Information-Features-Power handling: 50 watts per channel RMS; 150 watts peak Source input selectable, A or B switches Frequency response: 20Hz to 20kHz  1dB Attenuation: 11 Steps plus OFF Adjustable impedance matching. 4- or 8-Ohm speaker compatible Recessed area allows the use of custom labels or fine permanent markings Removable screw terminal connectors used with 12 to 22 AWG wiring : Interfaces/Ports-Interfaces/Ports-4 x Speaker Out, 2 x Amplifier In:Physical Characteristics-Height-2.5":Physical Characteristics-Width-17.5":Physical Characteristics-Depth-6.3": Power handling: 50 watts per channel RMS; 150 watts peak Selectable impedance matching for 1, 2, 3/4, or 5/6 speaker pairs Allows switching between 2 receivers and 6 zones with selectable impedance matching Features individual on/off selection for each room and 12-step volume control with 42 dB max attenuation Isolated inputs for compatibility with all amplifiers