The CK31 is a cardioid modular screw-on capsule with smooth response from 50 Hz to 20 kHz. All 30-series capsules feature pre-polarized condenser elements with gold plated contacts to ensure reliable connections and troublefree performance. The CK 31 capsule can be used with any of the "Discreet Acoustics Modular Series" installation modules. Each 30-series capsule has a dual layer windscreen; the dark gray outer layer disperses the impinging air stream while the inside layer smoothes the air stream before it reaches the diaphragm. This two-stage process efficiently reduces wind noise while maintaining acoustic transparency.