Small but very powerful: If you want to buy a small and lightweight personal voice amplifier, the S17 is for you. This is a portable microphone speaker with 30 watts of output power, which can greatly amplify your voice and protect your vocal cords, so you can easily make your voice heard. Voice for 25-100 people. Battery life: -- The small voice amplifier comes with a 2200mAh high-capacity rechargeable Li-ion battery that provides up to 12 hours of operation on a fully charged battery. Charging is easy with an included USB cable. And it only takes 3-5 hours to be fully charged. Convenient and portable: -- The portable speaker comes with an adjustable strap that can be tied around the waist or hung around the neck. The teacher speaker amplifier has a clip on the back, you can attach it to your belt or waist. The microphone on the wired headset is adjustable. Stable performance: This is an original voice amplifier with stable performance. The portable headset microphone has a flexible gooseneck design that sits right next to your mouth. Perfect for anyone who organizes events and needs 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 2.8 cm