【Intelligent Dynamic ANC 3.0】FreeBuds 6i's intelligent ANC 3.0 system gets to work cancelling out various kinds of noise, with the ability of monitoring environmental noises and adjusting the noise cancellation performance seamlessly, 5 kHz ultra-wide ANC frequency, 100% Noise Cancellation Capability Improved 【Punchy Bass】The 11 mm quad-magnet dynamic drivers are 50% more powerful and Hi-Res certified, producing as low as 14 Hz of punchy bass—performance that's sure to take your breath away. 【Fast Charging, Longer Listening】Listen for an astounding 35 hours with a fully charged case, or an impressive 4 hours after just 10 minutes of charging, to get going and grooving without missing a beat. ANC on, 20 hours of listening with a fully charged case, 5 hours of listening on a single charge. ANC off, 35 hours of listening with a fully charged case, 8 hours of listening on a single charge. 【Distraction-Free Calling】The earbuds come equipped with three microphones that work in tandem with deep neutral network (DNN) algorithm to distinguish voices from noise and cancel out noise during calls, so that you're heard loud and clear. 【IP54 Sweat- and Water-resistance】Explore the great outdoors or plunge into intensive workouts with peace of mind, with IP54 sweat- and water-resistance.