Bulk Packaging Overhead Earphone with Microphone/USB Plug and Inline Control for Calling Center Black30mm driver units of the earphone deliver clear balanced sound quality. Quality flexible noise reduction mic makes your voice can be clearly heard. Easily volume up down, mute or turn off mic via wired control. Soft PU leather ear cushions and ergonomic head beam ensure wearing comfort. Universal USB plug, widely compatible with laptop, desktop, corded telephone etc. Note: Please allow 1 3cm (0. 4 1. 18") difference due to manual measurement and