Crown CM311A Headset Microphone Item #: CRO CM311A 

The Crown CM311A Headset Microphone provides pro sound quality & performance and a very comfortable, secure fit making it one of the most popular headsets available.
Designed to sound every bit as crisp, full and rich as a great hand-held mic, the CM311A also rejects sounds coming from the back of the mic so it greatly reduces feedback & bleed from unwanted sources. Distortion free sound quality, light weight (2.1oz.) and dual power capability (9V battery or phantom power) make the CM311A the professional choice. Specs include 50Hz - 17kHz frequency response, 148dB SPL.

The CM311A offers cardioid performance in a comfortable headworn package. The CM311A is designed to meet the most demanding touring sound applications, with its electret condenser capsule providing full, clear and distortion-free sound. Gain-before-feedback and isolation are exceptional. Lightweight, rugged and comfortable, the headband and mic boom are adjustable to any vocalist. CM311A includes battery/phantom powered belt pack.