The Sony WI-C300 are wireless in-ear headphones designed to deliver extended listening time and lifestyle convenience for music lovers and audio aficionados relaxing, traveling, or studying inside or outdoors. Their 8.9mm dynamic drivers utilize neodymium magnets and produce a wide frequency response of 20 Hz to 20 kHz. The behind-the-neck design won't interfere with comfort or ease of use. Bluetooth version 4.2 and NFC technology grant simple and effective wireless integration with your mobile device.