Low voltage, low power consumption, power amplifier IC, quality, low distortion Built-in 180mAh battery, no external power supply required, offers one and a half hours of at maximum volume or around 2 hours at 50% volume Comes with an audio cable at the bottom of the speaker. Equipped with a USB charging cable design - retractable speakers. Small and light, hang hole design, easy to carry Suitable for , MP3, MP4, MP5, cell phones, computers and other devices with a 3.5 mm audio jack Colour:black Material:Silicone + metal Size:5.2 x 3.8cm Package Contents: 10 x Portable Travel Loud Speaker 10 x USB Cable 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.