The SSM2167 is a low-voltage, low-noise mono microphone preamplifier, ideal for low-power audio signal chains This preamplifier includes built-in compression and noise gates For this function, it is superior to using an operational amplifier in the preamplifier circuitry. Compressing the dynamic range of the microphone signal reduces signal levels and adds extra gain to low-level signals The noise gate attenuates the signal level below a certain threshold so that only desired signals such as speech are amplified, and noise in the output signal is reduced These features help improve the clarity of the speech signal received by the microphone. Due to different batches, there may be differences in product appearance and printed text, which not affect use Color:Red Material:PCB Package Contents: 3 * SSM2167 Microphone Preamplifier Module Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.