[Small but very powerful] - If you want to buy a personal voice amplifier that is small and light, then S17 is for you. It is a portable microphone speaker with 30 watts of output power, which can boost your voice significantly and protect your vocal cords, so you can easily let your voice be heard by 25 to 100 people. [ Lone Battery Life] - The small voice amplifier comes with a 2200mAh high-capacity rechargeable lithium-ion battery that provides up to 12 hours of operation on a fully charged battery. Charging is easy with a supplied 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 tie around your waist or hang around your neck. The teacher speaker amplifier has a clip on the back, you can clip it on a belt or waistband. The wired headset microphone is adjustable. [Stable performance] - It is an original voice amplifier with stable performance. The wearable headset microphone is a flexible gooseneck design that is positioned right near your mouth. Great for anyone doing events who need to project their voice. Suitable for teaching, coach, singer, trainer, tour guide, shopping mall, presentation, yoga, outdoor speech, etc. Size: 8.4 x 9.2 x 2.8cm