Composite metal diaphragm with the sandwich design which balance the middle - low frequency fidelity. Luca bignardi (the Grammy recording master) toned for this earphone, which hope to every can enjoy music with this MI dual sounder unit earphone. Precise CNC process for the unibody cutting, whose accuracy is up to 0.001mm. Fine 0.14mm CD pattern brings you the metal luster. In-line three-button remote control and one button for Microphone. Kevlar wire material which is wearable and anti-tangle.