TOZO NC9 Hybrid Active Noise Cancelling Wireless Earbuds, in Ear Headphones IPX6 Waterproof Bluetooth 5.3 Stereo Earphones, Immersive Sound Premium Deep Bass Headset Matte Black

【Active Noise Cancellation】Hybrid 3 layer Active Noise Cancellation. 1. Outward-facing microphone detects external sounds and counter with equal anti-noise to first cancel noise. 2. Inward-facing microphone listens inside ear canal to pick up internal sounds and produce anti-noise again to twice cancel the left noise. 3. Ear caps prevent 90% noise going to ear canal.