Rolls' MA252 is a compact class D stereo amplifier with a 4-channel 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. The MA252's overall dimensions 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.