7mm dynamic driver - Powered with Sennheisers audio expertise Battery life - Up to 9 hours play back time with up to 18 hours available with on the go charging via the case, for a total of 27 hours Passive Noise Cancellation and ergonomic design - Optimal comfort and secure fit to keep out all outside noise with 4 ear adapter sizes Intuitive touch controls - Easy control of music, calls and voice assistant IPX4 Splash resistance