... Consumption Current: 150mA Voltage: DC 7.5, li-ion battery Battery Type: Lithium Battery Size:95x80x35 mmColor: pink ,red,black,white Features:The ... long, can reach 15 hours ,Battery life can reach 2-3 years Cooperate with wearing type microphone Amplification effect is good ... levels of power efficiency. Class A amplifiers send a constant flow of power through the output transistors, resulting in low ...