The Rolls MA255 Compact Class D Stereo Amplifier features 20 watts per channel and a 4-channel integrated audio mixer. The MA255 is an ideal solution for mixing audio in halls, projection equipment, small presentations and other applications. The mixer features 4 RCA line inputs, and a 1/8" (3.5mm) mini input for connecting portable audio devices such as MP3 players (no mic input). Connect a pair of speakers right into the left / right speaker post outputs. Each channel features a level control dial on the front panel. The MA255 features a compact chassis and class D low heat emission, allowing it to be in tight spaces where proper ventilation would otherwise be an issue.