1) Zn alloy material body: ensures it to be durable. 2) 57mm titanizing diaphragm driver: lowers THD and make sound more powerful. 3) 3D sound effect: brings lively and stirring experience. 4) Support micro SD card playback. 5) Memory foam earmuffs for long-wearing comfort. 6) Line-in and line-out: Enjoy music even if battery runs out and also enables sharing music. 7) Foldable and flexible design: more convenient and portable.