4 Zons Class D P.A. AMP Series Function Introduction: Class D professional public address loudspeaker series is designed for small hotels, supermarkets and schools. They perform well and offer excellent sound quality. Besides, users can operate it easily. The Class D professional public address amplifier series has 7 inputs and 4 outputs. The series includes the following models: MPA-4150 (150W*4)/MPA-4250 (250W*4). The main functions are as follows:The series includes the followirg models:MA-2250 (250W*2)/MA-2500 (500W*2).