IMAGE Loud Portable Voice Amplifier LoudSpeaker Microphone for Teachers, Coaches, Tour Guides, Presentations, Salesman, Etc. This power Voice Amplifier use super capacitor,high performance Li-Lon battery as power supply. It is suitable for such application as teaching, Flow training & visiting, present performance and sales promotion in store supermarket or flow sales stand. The system is beautiful in small bodily form and easy to carry and operate, which makes it a wonderful aid for various activities. Note: please kindly contact customer service for help if you meet any problem with the product and we have been trying our best to enhance the quality. Thanks!