Korpa 
The Shure WH20 is a rugged, lightweight, dynamic headset microphone that provides high-quality voice pickup. It fits securely for active microphone users, such as aerobics instructors and musicians, with low visibility for stage appearances.
The cardioid (unidirectional) pickup pattern provides greater gain-before-feedback and isolation from ambient noise and other unwanted sound sources. A carefully shaped frequency response includes a voice-frequency presence peak and a low-frequency roll-off to compensate for the proximity effect inherent in cardioid mics during close-talk operation.
Features
Lightweight wireframe and elastic headband adjust for a secure, comfortable fit
Extra-strong, small-diameter attached microphone cable resists breakage
Collapsible microphone boom for easy storage and transportation
Smooth, natural frequency response comparable to high-quality dynamic hand-held vocal microphones
High input clipping level eliminates overload distortion
Reliable at temperature and humidity extremes
Supplied foam windscreen and clothing clip