Description: Built-in 2200mAh lithium battery, Battery life is very strong, 9 hours of use time, 3-5 hours can be fully charged Very clear sound, no background noise, the effective range of high-power speakers reaches 1000 square meters Attach a dual-use belt,the length of the waistband can be adjusted freely, with metal live buckles. With U disk and TF card dual socket, support U disk/ TF card playback,can be inked to computer tablet phones Suitable for: Teaching, tour guides, promotions, meetings, particularly if one is having trouble with one's own vocal volume. Specification: Type: Voice Amplifier Megaphone Booster Model: S17 Material: Plastic Size:(Lx Hx T)8.4 x 9.2 x 2.8cm/3.3 x 3.6 x 1.1 inch Battery capacity: 2200mAh Maximum use time: 9 hours Effective use distance:1000 Square Meter Color:Black/White/Rose Gold Suitable for: teaching, tour guides, promotions, meetings Package Includes: 1x S17 Voice Amplifier 1x Professional Microphone 1x Waistband Belt 1x USB charging cable 1x Receiver Note: 1.Please allow 1~3 cm error due to manual measurement, thanks. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Please understand, thank you.