Built-in 2200mAh large capacity 18650 battery, durable battery life, environmental safety, effective in teaching Strong and durable, combined with double layer, 3.5 plug with high strength metal, PVC wire tensile strength, good shielding U disk TF card double jack, can be linked to computer tablet phone Plug in the memory card /U disk can be a single cycle, listening to or learning, this function can repeatedly play the same clip Suitable for teaching/tour guide/party/speech/promotion/training and other scenarios Product name: Multi-function loudspeaker Input signal: microphone Battery capacity: 2200 mah 18650 battery Usage time: 20 hours Charging time: 3 hours Scope of application: teaching/tour guide/headset microphone/conference/training/listening to music size: 9.2 x 8.4 x 2.8cm Material: ABS colour: B-rose gold Package Contents: 1 x loudspeaker 1 x headset 1 x strap 1 x Charging cable 1 x English instructions Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.