Sony WIC400/B Behind The Neck Style, Wireless Headphone, Black BRAND NEW STILL INBOX comfortable, wireless Bluetooth headphones with up to 20 hours of battery life Enjoy music all way with these wireless Bluetooth and NFC in-ear headphones, with a comfortable neckband and up to 20 hours of battery life and hands-free controls. Easy Bluetooth connectivity with NFC One-touch, Up to 20 hours of battery life and Neckband for all-day listening. DRIVER UNIT: 9mm Frequency response : 8 Hz–22,000 Hz; MAGNET: Neodymium