FEATURES POLYSWITCHES SOLID-STATE CIRCUIT BREAKERS TO PROTECT THE UNIT FROM OVERLOAD & TURN OFF THE UNIT WHEN OVERLOAD IS DETECTED LISTEN TO ONE OR ANY COMBINATION OF SPEAKERS AT ONE TIME IMPEDENCE PROTECTION ALLOWS A SINGLE AMPLIFIER TO SAFELY POWER SEVERAL PAIRS OF SPEAKERSFOR 4 SPEAKER PAIRSUPC : 018359180724Shipping Dimensions : 12.80in X 8.70in X 3.00inEstimated Shipping Weight : 2.9