The Parasound Zonemaster ZM2 120 watts x2 @ 8 Ω 150 watts x2 @ 4 Ω or 2 Ω 4 speaker connections (A and B outputs for both channels) High current for stable operation at 2 Ohms Class AB input stage plus premium Class D power stage Audio sensing auto-on trigger 12 volt auto-on trigger input Looping 12 volt trigger output Speaker level input for expanding systems w/out pre out jacks Looping output to connect additional amplifiers Mono mode combines L and R for single speaker applications Separate level controls for both channels Detachable speaker connectors accept up to 12 gauge wire Short circuit and overheat protection with front panel indicators 0.5 watt standby power consumption meets Energy Star & EU specs Compact 1u, 1/2 width chassis size "ZRK" Rack mount kit sold separately Full Range Mono RCA Output 80Hz low pass Mono RCA output (for sub) Built in 80Hz low pass filter in bridged mode for driving in-wall/in-ceiling woofers or passive sub(s)