Smartphone Speakerphone: If you have a Bluetooth-compatible phone, you can pair them both to play your music files wirelessly, or stream from your favorite apps. When paired with a smartphone, you can use the built-in mic to transform the BT-155E into a speakerphone for hands-free calling. Built-In Controls-On the top of the BT-155E are tactile, rubberized buttons that let you manually controls the speaker. You can use them to switch to hands-free calling, play and pause music, pair it with a Bluetooth-compatible device, power it on and off, and adjust the volume. Specification: Version: 4.2 Capacity: 1200mah Rated Power: 3W Material:ABS+Metal， Transmission Distance: 10M Play times: 4-5 hours Function: BT/Subwoofer/TF/AUX-IN/FM Radio Dimensions: 8 x 5.5 x 5.5cm approx Colour: Red Includes: 1 x Speaker 1 x USB Cable