RoadKing RK56B Noise Canceling Mic wired 4 Pin CB Radio Cobra Galaxy Same microphone as RK564P except supplied in a Box instead of a costly display package. Dynamic Noise Canceling Microphone, black cycolac case, 4-Pin Connector 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 2 Position Momentary Slide Switch, Normally Open Contacts