Small but very cool: - If you are looking to buy a personal voice amplifier that is small in size and light, then the S17 is right for you. It is a portable microphone speaker with 30 watts of power, which can clearly amplify your voice and protect your vocal cords, allowing you to easily make your voice heard by 25 to 100 people. Single Battery Life: -- The small voice amplifier has a high-capacity 2200mAh rechargeable lithium-ion battery that provides up to 12 hours of operation from a fully charged battery. Charging is easy via a USB cable that is included. And it only takes 3-5 hours to fully charge. Convenient and Portable: -- Portable speaker comes with an adjustable strap that you can use to tie around your waist or hang on your neck. The teacher speaker amplifier has a clip on the back, you can attach to a belt or trouser waistband. The wired headset microphone is adjustable. Stable Performance: - It is an original voice amplifier with stable performance. The portable headset microphone is a flexible gooseneck design that is placed directly near your mouth. Perfect for anyone who does events and needs to project their voice. Suitable for teaching, trainer, singer, coach, tour guide, shopping mall, presentation, yoga, outdoor speech and etc. size: 8.4*9.2*2.8cm