The Sony WHULT900NW are Over Ear Wireless Noise Cancelling Headphones. They feature powerful deep sound designed to make your heart tremble. Prepare to feel the bass. Press the ULT button for powerful sound, thanks to the specially designed 40 mm driver unit and Integrated Processor V1. Enjoy precise, punchy, high-quality sound that gets you as close to the original recording as possible. Tailor sound to your personal preference. Choose from a variety of pre-sets to match sound quality with the genre of music you're listening to. With compatible smartphones and services, head tracking creates a realistic and compelling listening experience by automatically adjusting sound fields to compensate for your head movement. Sounds are precisely aligned with your smartphone screen, even as you move, to completely involve you in your viewing. With up to 30 hours of battery life, youll have enough power to keep listening all day and into the night. And if you need to top up in a hurry, a 3-minute quick charge will give you up to 90 minutes extra play time. Battery life is up to 50 hours with Noise Cancelling off.