Take Sound Reality on the go. The ATH-CKR35BT in-ear headphones feature Bluetooth wireless technology along with an in-line mic and controls, allowing you to answer calls, adjust volume and handle playback of music and videos on compatible smartphones and other devices. And with the headphones' high-performance 9.8 mm drivers and vibration-absorbing brass stabilizers, you're assured true-to-life audio with remarkably clear mid and high frequencies. The headphones feature compact housings designed to fit comfortably in anyone's ears and provide a high level of sound isolation - a fit enhanced by four sizes (XS, S, M, L) of interchangeable eartips. The in-line mic and controls are part of a comfortable behind-the-neck cord design that places the battery case on the upper back where, if desired, it can be attached to your shirt collar with the included clip. Also included are a 30 cm (11.8") USB charging cable and a protective pouch. What's in the box Headphones 4 different size housings USB Charging cable Battery Case Protective Pouch