Professional Active Noise Cancelling Technology. Significant noise reduction for travel, work and anywhere in between. Advanced active noise reduction technology quells airplane cabin noise, city traffic or a busy office, makes you focus on what you want to hear,enjoy your music, movies and videos. The noise cancellation function can work well both in wire and wireless mode. | 35 Hours Playtime Per Charge. A built-in 5V/0.5A battery won't allow your headphones power off, you can enjoy your world without noise for 35 hours' long time. Don't need to worry the power shortage problem on the long travel. | High-quality Built-in Microphone and NFC Technology. Harman Kardon provides high-quality built-in microphone for hands-free calls, Which is convenient for you to free yourself.