Noise Cancelling Headset Microphone for Audio-Technica Wireless Systems. Directional Characteristics: Noise Canceling (will eliminate the very low end sound & very high end sound for a smoother voice) Compatible with Audio-Technica Transmitters: ATW-T801, ATW-T27, ATW-T31, ATW-T51, ATW-T201, ATW-T210, ATW-T210a, ATW-T310, ATW-T310b for use with 200 Series, 1100 Series, 1400 Series, 1800 Series, 2000 Series, 2000A Series, 3000 Series, 3000A Series ** Important: For wireless receivers & transmitters of other brands, please contact us to check the compatibility first, even their connectors look identical. ** Minimize Background Noise to Capture the Most of User's Own Voice Ideal for speech, lecture, interview, and conference. (Not ideal for fitness classes)