The KZ ZS6 Dual Dynamic+Dual Customized Armatured Units Hi-Fi In-Ear Earbuds Wired Metal Earphone with Mic. The shell of this fantastic looking earphone was made of high quality aluminum alloy metal and precisely processed with CNC. The special customized balance dynamic driver units with reference level music details makes it a leap forward for headphone sound quality. For those who require better sound quality, the replaceable wire design allows you to change wire as needed. For example, you may change to Bluetooth module for wireless connection, or change to silver plated wire to enhance sound quality. This earphone meets the requirements of CNAS1454 quality standard.