Xiaomi Redmi Buds 4 Wireless Earbuds Hybrid Active Noise Cancelling & Dual Transparency Modes Bluetooth 5.2 in-Ear Earphones with 30 Hours Playtime Deep Bass Earphones for iPhone and Android With hybrid active noise cancellation technology, the feed-forward and feedback microphones work together to effectively separate background noise. Whether you're outdoors, on the bus or metro, one-touch for up to 35dB* noise cancellation. Redmi Buds 4 blocks out the hustle and bustle. Intelligent scene judgement based on ambient noise levels. Redmi Buds 4 intelligently switches between 3 ANC levels under adaptive mode supported by AI algorithm and offers a more comfortable noise-cancellation experience. The AI voice algorithm accurately differentiates human voice and ambient noise, so that even in the noisy environments, the listener will hear every word you say, loud and clear. Professionally tuned by Xiaomi Acoustic Lab*, extensive user audiology research. Fine-tuning based on the structure of the earbuds and acoustic principles produces a more professional frequency curve, deep bass and brighter vocals.