Small but very powerful -- If you are looking for a personal voice amplifier that is small and lightweight, then the S17 is the right choice for you. It is a portable microphone speaker with 30 watts of output power, which can clearly amplify your voice and protect your vocal cords, so that you can easily make your voice heard by 25 to 100 people. Long 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 the included USB cable. And it only takes 3-5 hours to fully charge. Convenient and portable -- The portable speaker comes with an adjustable strap that you can use to tie around your waist or hang around your neck. The teacher speaker amplifier has a clip on the back, you can attach it to a belt or waistband. The wired headset microphone is adjustable. Stable performance -- It is an original voice amplifier with stable performance. The portable headset microphone has a flexible gooseneck design that is placed directly near the mouth. Perfect for anyone who does events and needs to project their voice. Suitable for teaching, trainer, singer, coach, guide, shopping mall, presentation, yoga, outdoor speech and etc. Size 8.4*9.2*2.8CM