RP-HF400B Bluetooth® On-Ear Headphones At just 4.5 ounces, the HF400B headphones are ideal for extended listening comfort and they sync with all your Bluetooth devices. Large 30mm speaker drivers and acoustic bass control filters minimize distortion for strong bass, treble and vocals, and keep you going with up to 20 hours of playback when the headphones are fully charged. Free Up Your Music With the power and range freedom of Bluetooth, there are no twisted headphone wires to untangle or restrict you. The HF400B headphones sync to all your Bluetooth devices for high-quality sound from devices up to 33 feet away. 20 Hours of Playback Designed and styled for everyday use, these ultra-light wireless headphones keep you going with up to 20 hours of playback. Perfect for commuting, travelling, walking or relaxing at home. Power in a Hurry The HF400B headphones include a micro USB charging cord and built-in rechargeable battery that fully charges in 2.5 hours. But when the battery is low and time is short, a 15-minute quick charge provides enough power for over two hours of music. High-Quality Sound Enjoy every note, tone and lyric with large 30mm neodymium drivers and acoustic bass control filters for high-tone trebles and vocals, plus minimized distortion for sharp, lower bass tones. Ultra-Light Convenience At just 4.5 ounces, these feather-light headphones are not only ideal for extended listening comfort, their soft, padded earcups also swivel and fold flat to fit neatly into different size purses, packs, gym bags and briefcases.