Collect audio evidence as important as capturing video evidence, this preamp microphone kit is a perfect addition to any video security camera system. This high gain mini preamp and microphone is the best for CCTV professionals, with Preamplifier IC built on board, it increase a microphone"s low output voltage to a stronger, more usable level, it features low noise, high gain and auto level adjustment on-board preamp circuit. This mini-size microphone is only 5mm in diameter, easily hidden. Notice: This item is VideoSecu brand. Please report to Amazon.com if you received one without VideoSecu logo.