The ATH-CKS550BT Solid Bass wireless in-ear headphones give you the convenience of Bluetooth® and NFC wireless technologies, plus crystal-clear audio with refined bass reproduction. The powerful 9.8 mm Dual Magnetic-Field Drivers feature an extra magnet in front of the driver to create a concentrated magnetic field that helps produce full, textured bass without distortion. Audio-Technica's specially designed Multiple-Transition Diaphragms add to the expansive bass response, as does the new Bass Venting System, which provides excellent air damping. The ATH-CKS550BT wireless headphones feature a newly designed neckband that rests comfortably on the back of the neck and positions the in-line microphone, volume controls and music/video playback control in front of the neck for easy access. The headphones are equipped with Bluetooth® and NFC wireless technologies for quick pairing and automatic connection with the most recently paired device. The headphones' internal lithium polymer rechargeable battery provides five hours of continuous use and up to 200 hours in standby mode. A 1.0 m (3.3') USB charging cable is included, as are four sizes (XS, S, M, L) of interchangeable silicone eartips that press onto the headphones' unique two-position posts, supplying a custom fit with outstanding sound isolation. Available in black-gold (ATH-CKS550BTBGD) and white (ATH-CKS550BTWH).