Big Sound - Powerful driver with bass radiator for big sond and extra bass boost. Additional Anti-clipping function for loud, distortion free music. Strong Bluetooth connection - for wireless streaming with connection up to 30m or 100ft. Built-in microphone for hands-free phone calls. Intuitive charging - view power level with a bttery indicator. Super durability - Shockproof, dustproof and waterproof (IP57). Anti=Clipping lets you play music louder and keeps it high quality, even when the battery is low. This built-in function monitors the musical signal as it goes through the amplifier therefore preventing audio distortion. Durafit fabric covering the speaker provides both functional and aesthetic benefits. Dustproof, shockproof - tested in a torture chamber; to undergo a roller swing test with simulated 5-year product life-time reliability. And also water resistant, enabling immersion in water up to 1 meter for up to 30 minutes. Wireless music streaming with Bluetooth technology that is both robust and energy efficient. 1 speaker. Compatible with iPod, iPhone and iPad. Bluetooth compatible. 3.5mm AUX in. 4 watts per speaker. General information Size H8.6, W16.6, D2.2cm. Model number BT3900WT/00. Power from USB. USB cable included. Batteries required 1 x LiPo batteries (included) . Battery life 8 hours. (not included).