Waterproof Electret Condenser Microphones CUI Devices Waterproof Electret Condenser Microphones feature protection ratings up to IP67, sensitivity ratings as low as -42dB, and signal-to-noise ratios from 57dbA up to 70dBA. These omnidirectional microphones are available in wire lead and terminal mount configurations with operating frequencies ranging from 20Hz to 20,000Hz. CUI Devices Waterproof Electret Condenser Microphones are housed in compact packages with diameters as small as 4mm and depths as low as 1.5mm. These waterproof microphones are ideal for industrial and outdoor applications in which moisture and environmental contaminants are present.