Sony WI-C400 Wireless Behind-Neck In-Ear Bluetooth Headset with Earbuds - Black Easy Bluetooth connectivity with NFC one-touch • Up to 20 hours' of battery life • 9mm neodymium drivers for dynamic sound • Comfortable behind-the-neck style with cable management • Vibration for incoming calls • Connectivity Technology: Wireless NFC One-touch for instant connectivity Near Field Communication (NFC) and Bluetooth technology remove the need for wired connections and complex set-up sequences. Simply touch your NFC-enabled device to the headphones for a quick, seamless connection, then start streaming your music collection. No NFC? No problem. Connect via Bluetooth and you’re ready to go. Long listening time with up to 20 hours battery life Perfect for commuting or when you want to enjoy your music all day, when fully charged you can enjoy up to 20 hours of music playtime or talk time. Listen to your favorite music in private with this Sony wireless headset. It has a frequency response rate of up to 22,000Hz for increased clarity at top volumes, and the behind-the-neck design keeps it in place. This Sony wireless headset has a battery life up to 4.5 hours for short road trips.