Active noise cancellation to eliminate external noise while maintaining KEF's signature nuances and details. 8.2 mm dynamic full-range driver that reveals the smallest details of your favourite music Bluetooth 5.0 for exceptionally stable connections with iOS (iPhone) and Android devices. Ergonomically designed for comfort and fit, plus 4 sets of ultra-soft silicone earplugs for greater comfort and fit (large, medium, small, short). IPX5 splash-proof design for all weather conditions. Sound by KEF design by Ross Lovegrove. With KEF Mu3 wireless noise cancelling headphones, you can enjoy flawless sound anywhere. Designed to be both comfortable and elegant, each of the Mu3 headphones includes a dynamic 8.2mm dynamic driver. These are expertly tuned by the same KEF engineering team responsible for our speakers, ensuring consistently pure and precise sound on the go. Featuring rich mid-tones, detailed bass and crisp highs and able to reveal even the most subtle nuances of music.