1. Binaural design, freely switching between 3D<br>surround and common stereo sound<br>2. Noise-canceling and enhanced bass technology to<br>make voices sound more enjoyable.<br>3. All-metal sound chamber, aluminum alloy made<br>out shell, and excellent surface treatment process<br>4. 360 degree full coverage removable silicone ear<br>hook, ergonomic design, fit in different ear. Magnetic<br>adsorption function earplug design prevents falling<br>off