Headphone or speakerphone? Zoook jazz duo says both jazz duo makes the statement by transforming to one or the other with a push of one intuitive easy access control button. HD sound: 2-in-1 stereo Bluetooth v4.2 headphones and speaker system with deep rich bass and hd sound works with everything: Supports Bluetooth play/FM radio/ aux input / micro SD card / hands-free calls . Immersive sound experience: High performance 50mm premium driver with natural and balanced audio spectrum to deliver the dynamic music listening and hands-free talking experience. Comfort and convenience: Jazz duo offers the ability to keep the music to yourself when used as a headphone or play out loud via the 3w external loudspeaker, sharing is caring after all. Rechargeable battery: Built-in mic and high capacity 300mah lithium-ion rechargeable battery for maximum portability and convenience for up to 15hrs of music playtime in wired headset mode. Space-saving foldable headband travel companion: Allows simple transportation with its foldable headband design. Lightweight and lasting comfort: Large angle of rotation makes sure better fit. Soft leatherette foam ear pillows and literally weightless 135g ensures supreme comfort. Music sharing: Instantly share your music by using 3.5mm cables and connecting with second pair of jazz duo or headset.