



🔍 Hear what others can’t—unlock hidden conversations with pro-grade stealth tech!
The New F999B Super Sensitive Listen Thru-wall Contact/Probe Microphone Amplifier System is a professional-grade device designed to detect sound through solid surfaces like cement, metal, wood, and brick. Featuring four audio channels, up to 20,000x amplification, and 24-hour battery life, it offers unparalleled sensitivity and continuous monitoring. Its rugged metal housing and premium quartz crystal piezo microphone ensure durability and superior sound detection. Ideal for discreet surveillance, it comes with a private purchase option and a 5-year warranty, making it a top choice for serious professionals.
| ASIN | B01L9AMY9Y |
| Audio Sensitivity | 70 Decibels |
| Best Sellers Rank | #237,214 in Electronics ( See Top 100 in Electronics ) #1,441 in Audio Component Amplifiers |
| Customer Reviews | 3.5 3.5 out of 5 stars (25) |
| Date First Available | August 30, 2016 |
| EU Spare Part Availability Duration | 5 Years |
| Frequency Response | 20 KHz |
| Impedance | 32 Ohms |
| Is Discontinued By Manufacturer | No |
| Item Weight | 1.49 pounds |
| Item dimensions L x W x H | 9.06 x 7.09 x 2.76 inches |
| Item model number | F999B |
| Manufacturer | Kstpower |
| Material | Wood |
| Microphone Form Factor | Mini |
| Number of Channels | 4 |
| Power Source | Battery Powered |
| Product Dimensions | 9.06 x 7.09 x 2.76 inches |
| Signal-to-Noise Ratio | 70 dB |
| UPC | 723800422475 |
A**N
Great Basic Device
Reading others views here, I thought I would add my own opinion. Definitely a Chinese manufacture, and quality is so-so. Packaging and case quality are frankly horrible. That said, I am loving this device. Do not try to hold the probe manually; you cannot keep it still enough for decent signal. Nor can you tape to wall firmly enough. Find or create a flat surface to adjoin the wall - such as a large, flat book. Then find something nonmetallic and HEAVY to press against the fixture to create non-moving firm contact. The sound quality isn't what you would get from a mic inside the target area - but it is VERY close. I use an Olympus LS-P2 recorder that has two 3.5 openings - one for external mic and the other for a standard headphone. I tried buying a cheaper Olympus MP3 recorder for dedicated use with this mic, but it didn't process the incoming signal well; so you really have to get a decent recording unit assuming you do intend to connect the unit to a digital recorder. The unit also has several ports - FM transmitter (which I don't use), DC Charging port, Mic (for wall probe), REC - direct connection to your digital recorder and EAR - for headphones. So you can monitor the recording either through the device or through your recorder. As far as the 'do not overcharge' message - Ok, that's a bit unusual, but I just recharge when I am on hand to monitor it occasionally; it's probably not something you want to run off and leave. When the light turns green, it's done and you can unplug - not a big deal IMO and certainly not a dealbreaker or anything justifying less stars or a neg review. By the way the battery life is great. I had to leave this on for about 8 hours unattended and the unit worked very well. My advice is shop around. As good as this is, it is clearliy 80s/90s tech; it's enough for my use, but there are probably better things out there albeit more expensive. $105 for this kit is completely justifiable.
D**N
product critique
satisfied
A**R
Piece of crap doesn't work at all don't buy
Doesn't work a clear ripoff don't buy from this company or seller
Z**N
Four Stars
Good stuff easy to handle.
B**.
Trash doesnt work, wast of money,worthless
there's nothing to like the xxx thing does nothing
L**R
Works very well! Finding leaks! :-)
While I did not use it for its intended purpose, I got this to help me find a leak in the wall, I got the idea from someone on Youtube. One can set the frequency and found a water leak before it became a horror story. Took a bit of getting used to it. But a steady had to hold the probe and patiences came within a few inches of the source of the sound. (Note slow drips are harder) But this was a streamer..... Definitely a nice thing to add to the toolbox.
Trustpilot
2 weeks ago
2 weeks ago