Understanding the Faraday Principle
A Faraday bag functions as a portable electromagnetic shield. The concept is based on the Faraday cage – a conductive enclosure that redistributes electromagnetic energy around its surface, preventing signals from entering or escaping.
When a device such as a smartphone, tablet or laptop is sealed inside a Faraday bag, the external electromagnetic fields including WiFi, Bluetooth, cellular, GPS and RFID are reduced to levels far below what is required for communication. This prevents wireless tracking, remote access, and data interception.
Not all Faraday bags achieve the same level of isolation. The effectiveness depends on the quality and integrity of the materials used, the number of shielding layers, and the precision of the construction. Leblok Security Faraday bags are engineered to deliver reliable, measurable attenuation across a wide frequency range, ensuring consistent protection even under demanding conditions.
Construction and Materials
Every Leblok Security Faraday bag is built from specialised high-performance RF shielding material combined with a durable ripstop outer layer. This multi-layer design ensures complete shielding continuity across seams and closures, preventing signal leakage that can occur in less precise constructions.
The core shielding fabric provides attenuation levels of up to 85 dB per layer when independently tested to ASTM D-4935-10 and IEEE 299-2006 standards. Leblok’s Faraday bags for phones, tablets and laptops – use three layers of this material, delivering exceptionally high isolation against electromagnetic fields across all major consumer and professional frequencies. The compact Key Fob Bag uses a single layer, which is sufficient to block the much weaker signal strength of automotive keyless entry systems.
The result is a consistent, high-performance barrier that protects sensitive electronics and personal data from unauthorised access, tracking and interference.
Shielding Performance
Test results shown are for a single layer of shielding material. Leblok Faraday bags use a three-layer construction for enhanced protection.
| Frequency | Shielding | Standard |
|---|---|---|
| RFID 13.56 MHz | 80 dB | ASTM D-4935-10 |
| C-Net, TETRA, 450 MHz | 80 dB | ASTM D-4935-10 |
| D-Net, GSM900, 900 MHz | 83 dB | ASTM D-4935-10 |
| E-Net, GSM1800, 1800 MHz | 85 dB | ASTM D-4935-10 |
| Blue-Tooth, WLAN 2450 MHz | 84 dB | ASTM D-4935-10 |
| 5G (Sub 6 GHz-Band) 3.4 – 3.8 GHz | 85 dB | ASTM D-4935-10 |
| W-LAN new generation 5.8 GHz | 75 dB | ASTM D-4935-10 |
| 7.5 GHz | > 42 dB | IEEE 299-2006 |
| 10.0 GHz | > 42 dB | IEEE 299-2006 |
| 12.5 GHz | > 42 dB | IEEE 299-2006 |
| 15.0 GHz | > 42 dB | IEEE 299-2006 |
| 18.0 GHz | > 42 dB | IEEE 299-2006 |
| 30 GHz | > 52 dB | IEEE 299-2006 |
| 35 GHz | > 52 dB | IEEE 299-2006 |
| 40 GHz | > 52 dB | IEEE 299-2006 |
| *Tested at the German Armed Forces University, Munich, Germany. | ||
This performance demonstrates that Leblok Security’s Faraday bags not only block everyday consumer frequencies but also provide shielding in the professional and defence-related spectrum bands. The design also offers protection against electromagnetic pulses (EMP) by reducing field strength to levels incapable of inducing damaging currents in the contained device.
Why Layering Matters
Each shielding layer in a Faraday bag acts as a conductive barrier. Using multiple layers of suitable shielding material greatly improves overall attenuation by increasing both reflection and absorption of electromagnetic energy.
While single- or dual-layer consumer pouches may limit some signals, they often leave residual leakage strong enough for partial or full connectivity. Leblok Security’s triple-layer configuration ensures signal isolation sufficient to fully prevent connection, even in strong-signal environments such as airports and data centres.
Quality and Manufacturing
All Leblok Security Faraday bags are designed and manufactured in the United Kingdom under ISO 9001 quality standards. Every production batch is verified for shielding consistency, seam integrity and closure reliability.
The outer rip-stop material adds durability, water resistance and resilience to wear, making the bags suitable for both field operations and everyday professional use. This combination of engineering precision and material performance provides dependable protection without unnecessary bulk.
Practical Applications
Corporate and Government Security
Preventing wireless data exfiltration during travel or confidential meetings.
Law Enforcement and Forensics
Preserving mobile evidence by isolating it from the network.
Defence and Technical Operations
Shielding mission-critical equipment from RF intrusion.
Personal Privacy
Stopping tracking and unauthorised access to mobile devices.
By providing a portable shield against wireless connectivity, Leblok Security Faraday bags help users maintain control over their digital exposure – an increasingly important aspect of information security.
How to Test Your Faraday Bag
Testing your Faraday bag properly ensures it delivers full signal isolation across all key frequencies — not just mobile networks. Follow these steps for a reliable assessment:
1. Cellular Test (Basic Check)
- Place your smartphone inside the Faraday bag and seal it completely.
- Ask someone to call your number.
- If the call fails to connect, the bag is at least attenuating mobile signals.
Note: Even lower shielding level bags often pass this test, so continue with Wi-Fi and Bluetooth checks.
2. Wi-Fi and Bluetooth Test (Critical Check)
- Turn on both Wi-Fi and Bluetooth on your device.
- Place the device in the sealed Faraday bag.
- Using another device (like a laptop or tablet), search for its Wi-Fi hotspot or network presence.
- Detect the phone via Bluetooth pairing
- It the phone still appears and connects, the bag is not providing full shielding against high-frequency signals.
Frequently Asked Questions
What does a Faraday bag do?
A Faraday bag blocks external electromagnetic signals such as WiFi, Bluetooth, cellular, GPS and RFID by enclosing devices in a conductive barrier. This prevents communication, tracking, and data interception.
Why to use Faraday bags instead of simply switching devices off?
Even when switched off, many modern electronic devices continue to communicate. Background systems can stay active for location tracking or remote access, as seen with Apple’s Find My functionality. For anyone responsible for protecting confidential data or conducting sensitive work, simply powering a device down is not enough. A Faraday bag offers assurance by physically isolating the device and blocking every form of external signal.
How effective are Leblok Security Faraday bags?
Leblok Security Faraday bags use specialised high-performance RF shielding material in triple-layer construction. Independently tested to ASTM D-4935-10 and IEEE 299-2006 standards, they provide signal attenuation exceeding 85 dB per layer and reliable isolation across all major consumer and professional frequencies.
Do Leblok Faraday bags protect against EMP?
Yes. The multi-layer shielding design reduces electromagnetic pulse energy to levels incapable of inducing damaging currents in the device, offering effective EMP mitigation.
For additional answers including practical use and testing, visit our Faraday Bag FAQ page
Learn More
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