The Rolls MA252 is a compact class D stereo amplifier with a 4 CH. stereo mixer built in. It has 20 watts per channel @ 4 Ohms. The class D low heat design gives the MA252 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 MA252 is in an all metal chassis and weighs 1 pound. Overall dimension are 6.75” X 3.5” X 1.5”. Bottom mounts are provided for permanent installations. The MA252 has an included 24 VDC 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 MA252.