Konstar Wireless Speaker with Dual 10W Drivers and Built in 4000Mah Battery - Black Superior Sound Quality:Advanced digital sound,noise/wind reduction technology,and unique loudspeaker cavity structure to deliver premium acoustic sound,crystal clear balanced bass(20W) Incredible Battery Life:Built-in high capacity rechargeable Li-ion battery(4000mAh), supports up to 20 hours playing time at the volume to 70% of the maximum volume Bluetooth 4.0 Technology: Compatible with all Bluetooth-enabled devices. Instantly connect to your Iphone/Ipad or tablet from up to 10m away. SoundCore reconnects automatically to the last device used. Built-in micphone for hands-free calls. so you can conveniently pick up a call by this bluetooth speaker This bluetooth speaker with USB TF Card Slot You Can Play the Mp3 Format Music Which Storaged in Usb Tf Card,Built-in Microphone, Support Hands-Free Calling What you get: Konstar Bluetooth speaker, Micro USB charging cable,Aux in cable,user manual ,remote controller and friendly customer service, and 30-day money back guarantee