Dedicated Amplification System for 76 and 61 key models. 3 Channel Amplifier: 2x20 Watt (Mid/Hi) + 1x40 Watt (Subwoofer). 5 Speakers: 2 Midrange (80mm), 2 Tweeters, Dual Coil Woofer (130mm). Cabinet: Aluminium case with Bass Reflex System Connectivity: through custom connector. No audio cables and no power supply needed. Dimensions: 992 x 173 x 137 mm / 39.06 x 6.81x 5.39 inch