Specifications High Pass Crossover 60Hz?600Hz Max Power Rating (Watts):D-Class 70 Watts Operating Range 10 -16 volts DC Ratings per Channel 20 Watts RMS @ 4 ohms per channel: 33 Watts RMS @ 2 ohms per channel Marine Zone Amplifier FUSION's Marine Zone Amplifier is designed to support the multi-zone technology of the Marine Stereo Unit. The Zone Amplifier is small,enabling discrete installation and when combined with the Marine Stereo Unit provides the platform for a True multi-zone audio system. WHY DO I NEED A ZONE AMPLIFIER? A Marine Zone Amplifier is needed if you are planning a multi-zoned system, comprising of three or four zones. System # Speakers Zone Amplifier Needed 1 Zone System 1-4 pairs of speakers No 1 Zone System More then 4 pairs of speakers Yes 2 Zone System 1-4 pairs of speakers No 2 Zone System more then 4 pairs of speakers Yes 3 or 4 Zone system   Yes FUSION?s Marine Stereo Units have the capability to run up to four pairs of speakers. You will also need to install a Marine Zone Amplifier if your sound system has more than four pairs of speakers 2 Channel 2 Ohm Stable Water resistant design Conformal coated PCB Audio detect selectable function the amplifier turns on when audio is detected and goes to sleep / low power mode when audio is not present Selectable high pass/ full range setting Variable high pass filter Small and discrete size: 128 x 78 x 51mm