Sound driven performance helps boost your workouts. Enjoy a comfortable and secure fit with ear adapters and ear fins. Sennheiser signature sound with a TrueResponse transducer. Built-in Equalizer controlled through Smart Control app. IP54 Rated dust splash and sweat resistance. Tough design lasts for long use. Up to 9 hours of playback - additional 18 hours with case. Built-in microphone supports hands-free calls. Frequency range: 100Hz to 10kHz. Includes: USB-C charging cable. Closed and Open ear adapter sets (S/M/L). Ear fins sets.