Take your music wherever you go with the help of Sony C400 Wireless Behind-the-Neck In-Ear Headphones. The U-shaped headphone neckband lets you manage your bud cables and store them neatly when not in use, and the the long-lasting rechargeable battery gives you all-day sound for wherever your next adventure takes you.NFC One-touch for instant connectivityNear 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 youre ready to go.Long listening time with up to 20 hours battery lifePerfect 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.Neckband for all-day listeningShaped for comfort, the lightweight neckband allows you to wear your headphones all day, keeping the earbud in place.Cable managementThe cable can be stored tangle-free and neatly held in place with the cable adjuster and stopper, keeping it out of the way.Vibrating neckband for callsYour neckband will vibrate to let you know you receive a call, so you wont miss a thing.Easy operation with buttonsUse the buttons to play, stop or skip through tracks and adjust the volume. You can also push them to activate your smartphones voice assistant features or make hands-free calls.8Hz - 22kHz headphones frequency responseAlong with a 50Hz - 8kHz microphone frequency response ensures faithful sound reproduction.9mm driversDeliver powerful sound.