The new MA251 is a compact class D stereo amplifier with a 4 CH. stereo mixer built in. It has 5 watts per channel @ 4 Ohms. The class D low heat design gives the MA251 the ability to be mounted in very tight applications. It will work great in ceilings by projectors, or anywhere small and heat free amplification is required. The MA251 is in an all metal chassis and weighs 1 pound. Overall dimension are 6.75” X 3.5” X 1.5”. The MA251 has an included 12 VAC external power supply. The 4 channel mixer section consists of 2 separate RCA stereo inputs, along with an XLR mic input and a 3.5mm (1/8”) stereo input perfect for an ipod or laptop computer type input. Phantom power is supplied to the XLR input by a switch on the back of the MA251.