The CM311 reference head-worn condenser microphone is designed for touring and live-sound applications. It sounds like the best handheld microphones - full, clear and distortion-free, even with the loudest singers. Differoid® stands for differential cardioid, which cancels ambient noise from floor monitors, crowds and other sources. Controlled field tests show that the Differoid provides up to 12dB more gain before feedback than conventional cardioid microphones. Many users of CM311 say that their house mix is better because the mic''s isolation is nearly complete. The CM-311 L is terminated with a female professional mini-XLR connector for use with all AKG wireless body-pack transmitters. The microphone comes with a custom molded hard plastic case. Differoid noise-cancelling technology for highest ambient noise rejection Cardioid polar pattern for outstanding gain before feedback Condenser capsule with internal shock mount for efficient rejection of mechanical and body noise Robust headband construction for maximum comfort and freedom of movement