High Sensitive Audio Pickup Tiny Mini Mic Microphones for CCTV Home Surveillance Security Camera - 4 pack (Warranty 14 months) 1. Unique service can make you rest assured to buy--(1)Warranty 14 months,a warranty system, to provide repair parts. (2) Professional sellers, and professional guidance, have more cctv accessories to choose. (3)Provide professional use tutorials. (4) Often give away free tool products (because we clean stock). Please contact us if you need any of the above services 2. No noise, no loud hum(buzzing) -- picking up clean audio and no buzz with some kind of interference. It picks up about 25ft to 50ft depending on here its installed near a reflective wall . Beware if it's exposed to pouring water it will stop working. Try and install your mic under a place where it won't get rained on 3. This high gain mini preamp microphone is the best for professionals -- Widely used in banking, finance, shopping malls, prisons, justice, classrooms, conference rooms, industrial production, military areas, and many other places 4. Collect audio evidence as important as capturing video evidence -- this microphone is compatible with devices that accept AV input, like TV, VCR, DVR. Pick up every sound with this super high gain micro audio system. bonus warning sticker is included 5. A combined power and audio cable are included with the microphone -- 1 ft cable attached with a RCA connector for audio and a power plug of 2.1mm center positive. Pick up every sound with the super high gain micro audio system. Built in on board IC preamp, low noise, high gain and auto level adjustment