Features: GOOD HELPER FOR YOU: Amplifying your sound on busy occasion. This voice amplifier can provide clear and smoothing sound to cover in the classroom, let everyone hear what you are saying. HIGH SOUND QUALITY: 3D surround sound field, provides high sound reproduction and clearer sound quality, makes your voice clear and smoothing and does not produce loud-noise. SMALL AND PORTABLE: The size is only 9.2x8.4x2.8cm, compact and lightweight, it won39;t carry too much burden. Comes with an adjustables strap and clip, allows you to wear it at the waist or hangs it from the neck. MUSIC PLAYER FUNCTION: Supports USB flash-drive playback and TF card playback, you can repeat a single melodys, loopingall music and switch songs / record content, you will never missing any important information again WIDE USE:Ideal for teachers, tour-guides, physical trainers and anyone who needs to improve their sound. For classrooms, conferences, speeches, trainings, meetings, shopping centers, etc. Notice: 1.Actual color may be slightly different from the image due to different light effect 2.Please allow 1-3cm deviation due to manual measurement Description: Size: 9.2*8.4*2.8cm Battery capacity: 2200 mAh Package List: 1 Set Portable Amplified-Speaker for Teachers