1. Automatic noise reduction, to avoid sudden loud damage to the ears; 2. Rechargeable design, longer life, save the trouble of replacing batteries; 3. Nano-coating, limited anti-sweat and waterproof, protects the built-in chip; 4. Smart chip, no fitting required; 5. One switch key, one volume adjustment key, easy to use; 6. FCC, ROHS, CE, EMC certification;