MB Quart Formula series compact five channel car audio amplifier featuring innovative sound quality and power technology to run four full range channel and a subwoofer channel. The FA2-900.5 is a 900 watt 1 ohm stable (channel 5 only) car audio amplifier. Formula amplifiers feature DC Sensing to allow any amplifier to be easy integrated into an OEM system by simply adapting a RCA cable from the source unit. Bass remote is included.