RoadKing RK564P 4-Pin Dynamic Noise Canceling CB Microphone 4-Pin Connector Dynamic Noise Canceling Microphone, black cycolac case 2 Position Momentary Slide Switch, Normally Open Contacts Frequency Response: 100Hz - 8kHz, Output Level @ 1kHz Output Impedance: 2000 Ohms (Matches 600-5000 Ohm Inputs) Open Circuit: -72dB (ret. 0dB = 1V/Ohm Bar Power Level: -55dB (ret. 0db = 1Mw/10 Ohm Bar