Hear more than music: Unleash your workout's full potential with Sennheiser's sport sound profile, adaptive ANC, transparency mode and robust bass for immersive sound and focused training Fitness tracking powered by Polar: In-ear sensors for real-time heart rate and body temperature tracking, syncing seamlessly with apps and devices for insightful health and performance metrics Custom fit for every athlete: Secure fit with interchangeable ear fins and tips for a snug, comfortable fit, plus IP55 sweat and splash resistance - Ideal for every ear shape and workout intensity Extended battery life: Never miss a beat with 24 hr total playtime (6 hrs earbuds + 18.5 hrs case) - Quick charge ensures 45 mins of playtime with just 10 mins of charging Effortless control: Smart UI with tap controls for effortless, precise earbud management during intense workouts so you can focus on achieving your fitness goals