ANN 3.0: Intelligent Dynamic The clever ANC 3.0 system in the FreeBuds 6i starts to eliminate different types of noise. It can monitor background noise and smoothly modify the noise cancellation performance. An ultra-wide ANC frequency of 5 kHz and an improved 100% noise cancellation capability Punchy bass can be heard as low as 14 Hz thanks to the 11 mm quad-magnet dynamic drivers, which are 50% more powerful and Hi-Res certified. The performance will astound you. Quick Charging, Extended Listening With a fully charged case, you can listen for an incredible 35 hours, or an amazing 4 hours after just 10 minutes of charging, so you can start moving and having fun without missing a beat. ANC on, five hours of listening on a single charge, and twenty hours of listening with a fully charged case.