Micro Wall Bug – Hear Through Glass Using Piezo Sensor & Transmit Audio to an FM Radio (Spy-IL4)
Spy-IL4 Micro Wall Bug — Vibration (Piezo) Glass/Wall Audio Monitoring Transmitter
• Designed for discreet sound acquisition through glass and thin surfaces
• High-sensitivity piezo vibration sensor converts glass vibrations into a clear audio signal
• Compatible with a standard FM radio receiver (receiver not included unless stated)
• Powered by 2× CR2032 batteries — up to 24 hours continuous operation (conditions dependent)
What Spy-IL4 Is
Spy-IL4 Micro Wall Bug is a compact audio monitoring transmitter built for scenarios where unnoticed capture of sound information is required through glass (and other thin vibrating surfaces). Instead of a conventional air microphone, it uses a high-sensitivity piezo vibration sensor that detects micro-vibrations caused by speech and converts them into a clean wireless audio signal.
How It Works
When people speak, sound waves make window glass vibrate. The built-in piezo sensor captures these vibrations, amplifies them, and feeds the transmitter. This approach works in situations where a standard microphone cannot be placed near the source or where an air microphone would be easy to notice.
Installation
The unit mounts directly onto glass using the included double-sided adhesive tape. Installation is fast, clean, and does not require drilling or damage. Once mounted, the device operates silently and transmits live audio in real time to a compatible FM receiver.
Power & Battery Care
Power is supplied by two CR2032 lithium batteries, providing up to 24 hours of continuous operation (depending on conditions). The device has no on/off switch: it turns on when both batteries are inserted and turns off when they are removed.
Important: to preserve battery life, remove both batteries immediately after use and store them separately — leaving batteries installed may cause them to discharge.
Signal & Receiver
The ultra-thin antenna is designed for efficient transmission while remaining visually discreet. Audio can be received using a standard FM radio receiver (receiver is not included unless stated in the package).
Legal notice: This product is supplied for lawful use, technical testing, and educational purposes only. The buyer is solely responsible for ensuring compliance with local laws and regulations regarding audio monitoring equipment.
▸ Specifications
- • Device Type: Micro Wall Bug (FM audio monitoring transmitter)
- • Audio Function: Live audio transmission only (no internal recording)
- • Frequency Range: FM band (device is tuned/adjusted for operation; reception via FM receiver)
- • Operating Range: Up to 200 meters (approx., conditions dependent)
- • Sensor / Microphone: High-sensitivity piezo vibration sensor (glass vibration pickup)
- • Receiver Compatibility: Standard FM radio receiver (not included unless stated)
- • Power Supply: 2 × CR2032 lithium batteries
- • Operating Time: Up to 24 hours continuous operation (conditions dependent)
- • Power Control: No switch — ON when batteries inserted / OFF when removed
- • Recommended Environment: Controlled area; best results on clean glass / thin vibrating surfaces
- • Country of Origin: Made in Israel
*Real-world performance depends on obstacles, RF noise, glass thickness, installation quality, and the receiver used.
▸ Videos
▸ Frequently Asked Questions
▸ Does this device record audio?
▸ Is a receiver included?
▸ How does the piezo sensor work on glass?
▸ Is this product legal to use?
▸ What if I need help with setup or want to return the item?
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