Koss Corporation announced the release of the BT539i Wireless Bluetooth® Headphones. The Koss BT539i Wireless Bluetooth® Over-Ear Headphones pack powerful wireless sound into a portable, fold-flat unit. The Koss BT539i Wireless Bluetooth® Headphones have the natural fitting, iconic “D-profile” earcup, first featured on the ergonomically designed Koss Pro4AAA and now available on many Koss headphones. The D-profile mimics the shape of the ear, creating an excellent seal for the most consistent sound reproduction. Listeners can stay connected using the built-in microphone. Easy to locate, on-board controls allow listeners to quickly navigate through songs, play or pause music, control volume levels, and answer incoming calls. The built-in rechargeable lithium-ion battery delivers up to 10 hours of play time or 9 hours of call time (at moderate levels) and 40 hours of standby time on a single charge. If the rechargeable battery runs out, the BT539i comes with a detachable analog cord, which can be used as an audio bypass. Closed ear cushions seal comfortably around the ears to block outside noise and keep music from leaking out. The Koss BT539i Wireless Bluetooth® Over-Ear Headphones fold flat into a convenient size that is easy to carry and even easier to store. The Koss BT539i Wireless Bluetooth® Over-Ear Headphones are available immediately for $99.99.