Do Faraday Pouches Actually Work? Testing the Claims

Faraday pouches are the most common recommendation for preventing relay attacks. Put your key fob in the pouch, the signal is blocked, thieves can't relay it. Simple, cheap, effective. At least, that's the theory.

We tested five popular Faraday pouches—ranging from $8 to $35—to see how well they actually work.

The Test Setup

We used a key fob from a 2023 Range Rover (one of the most targeted vehicles) and a commercially available relay amplifier—the same type used in real thefts.

For each pouch, we tested:

• Signal blocking when sealed properly
• Signal blocking when slightly open
• Signal blocking after 6 months of use (wear and tear)

Results: When New and Sealed

Good news first: all five pouches blocked the relay signal when new and properly sealed. The relay device couldn't pick up the key fob from any reasonable distance (we tested up to 50 feet).

Results: When Slightly Open

Here's where things get concerning. With the pouch flap slightly open—simulating careless closure—results varied dramatically:

• 3 pouches: Signal still blocked (good RF shielding design)
• 2 pouches: Signal detectable at 10+ feet (single-layer construction)

The cheaper pouches ($8-$15) generally had single-layer construction that allowed signal leakage when not perfectly sealed.

Results: After 6 Months of Daily Use

We simulated wear by opening/closing pouches 500+ times and testing with keys in pockets (compression, friction). Results:

• 2 pouches: Still fully effective
• 2 pouches: Some signal leakage when sealed (degraded shielding)
• 1 pouch: Failed completely (torn RF layer)

The Bigger Issue: Human Error

Even assuming a perfect pouch, there's a more fundamental problem: you have to use it correctly, every single time.

• Keys on the kitchen counter while making dinner? Vulnerable.
• Keys in your pocket while at a car meet? Vulnerable.
• Forgot to put keys in pouch after unlocking the house? Vulnerable.
• Spouse/valet/family member doesn't know about the pouch? Vulnerable.

A Faraday pouch requires 100% compliance to provide 100% protection. One slip—one time leaving keys exposed near a window—and you're at risk.

Our Recommendation

Faraday pouches are better than nothing. If budget is the primary constraint, get a quality dual-layer pouch from a reputable brand and commit to using it religiously.

But recognize the limitations:

• They degrade over time with no warning
• They require perfect compliance
• They don't protect against OBD/CAN bus attacks
• They're a band-aid on a fundamental design flaw

For high-value vehicles, adding a digital immobilizer provides protection that doesn't depend on your behavior. Whether you remember to use a pouch or not, whether your keys are exposed or not—the car won't drive without your PIN.