Low voltage, low power consumption, power amplifier IC, high quality, low distortion. Built-in 180mAh battery, no external power supply required, offers one and a half hours of playtime at maximum volume or around 2 hours at 50% volume. Comes with an o cable at the bottom of the speaker. Equipped with a USB charging cable. Unique 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 o jack. Color: black. Material: Silicone + metal. Size: 5.2 x 3.8 cm. Package Contents: 1 * Loud Speaker, 1 * USB Cable. Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture to be slightly different from the real thing. The measurement allowed error is +/- 1-3 cm.