Key Fob & Relay-Attack Protection

The amplifier reaches your driveway. The signal never leaves the bag.

Faraday-shielded protection that stops relay-attack theft on Range Rover, BMW, Mercedes, Tesla, Lexus, Audi, Porsche. Blocks every key-fob frequency — 315/433/868/915 MHz LF plus 2.4 GHz Bluetooth phone-as-key. 76–85 dB attenuation across 30 MHz – 10 GHz.

Verified vs. Range Rover Verified vs. BMW · Mercedes Verified vs. Tesla · Lexus Phone-as-Key Compatible
Definition

How a Faraday bag stops a relay attack.

A relay attack is a two-person theft technique that extends the radio signal between a parked car and the owner's key fob inside the house. Faraday shielding mathematically blocks that signal from leaving the bag. With the fob inside the REVIS-1, no signal escapes, no signal can be amplified, no signal can be relayed. The car cannot be relay-attacked because there is nothing to relay.

This is the only physical defense that works on every variant. Software updates from the manufacturer help; ultra-wideband ranging in newer fobs helps; parking inside a metal garage helps. But none of those are universal, and most luxury vehicles built before 2024 do not have UWB ranging at all. Faraday is the universal physical layer.

The REVIS-1 is verified against the LF wake-up frequencies used on Range Rover and Land Rover (the most-stolen vehicles in this category by absolute numbers), BMW M-series and X-line, Mercedes-Benz S-, G-, and AMG-line, Tesla Model S/X/3/Y, Lexus LX/LS/RX, Audi RS line, and Porsche Cayenne/Panamera/Taycan. Same Faraday principle covers Bluetooth-Low-Energy phone-as-key implementations (Tesla, BMW Digital Key, Apple CarKey).

Threat Model · The Attack in Four Steps

Under 30 seconds, end to end. No window broken. No alarm tripped.

STEP 01

Approach the house

Thief A walks to the front door with a battery-powered LF amplifier (cost: ~$150 from electronics suppliers). The fob inside the house is constantly listening for the car's wake-up signal.

STEP 02

Capture & relay

Thief B stands at the car and pulls the door handle. The car emits its LF wake-up signal. Thief A's amplifier captures that signal at the door, retransmits it inside to the fob, captures the fob's response, retransmits it back to the car.

STEP 03

Door opens & engine starts

From the car's perspective, the genuine fob is right there. Door unlocks. Engine starts. Thief B drives away. Thief A walks to a second car parked nearby and follows.

STEP 04

Most owners notice the next morning

Average detection time on relay theft: 6–8 hours, because the attack happens at 2–4 a.m. and there is no audible alarm. By the time the owner reports the theft, the vehicle is in a chop shop or on a container ship.

Verified Coverage

Vehicles tested against the REVIS-1.

Brand & Line
LF Frequencies
Phone-as-Key
Status
Range Rover · Land Rover
315 / 433 MHz
Activity Key (no BLE)
Blocked ✓
BMW · all lines incl. M-series
315 / 433 / 868 MHz
BMW Digital Key (BLE 2.4 GHz)
Blocked ✓
Mercedes-Benz · S, G, AMG, EQS
125 kHz / 433 / 868 MHz
Mercedes me Connect (BLE)
Blocked ✓
Tesla · Model S / X / 3 / Y
315 MHz (key fob)
Phone Key (BLE 2.4 GHz)
Blocked ✓
Lexus · LX, LS, RX
315 / 433 MHz
Lexus App (limited)
Blocked ✓
Audi · RS line, Q-line, e-tron
433 / 868 MHz
myAudi (BLE)
Blocked ✓
Porsche · Cayenne, Panamera, Taycan
433 MHz
Porsche Connect (BLE)
Blocked ✓
Ford · F-150 Lightning, Mustang
315 / 902 MHz
FordPass Phone-as-Key
Blocked ✓
Toyota · Land Cruiser, Lexus LX
315 / 433 MHz
Toyota App (limited)
Blocked ✓
Daily-Use Protocol

How owners actually use the bag.

01

The evening drop

Walk through the door, drop keys + phone + wallet into the REVIS-1. The bag stays at the entryway. Relay attack cannot complete because the LF signal does not exit the bag. Pick the bag back up in the morning. This is how 70%+ of repeat buyers describe their daily use.

02

The travel carry

For business travel and weekend trips, the bag is the briefcase. Phone, MacBook, key fob, RFID wallet — all in three independent chambers. Boardroom-appropriate optics. Cabin-carry friendly. Doubles as an executive briefcase that nobody mistakes for a security product.

03

The detail / family-office standard

EP details, single-family offices, and HNW principal-protection programs standardize the REVIS-1 as the default carry. Custom-branded Velcro patches identify the principal or detail without naming the manufacturer. Bulk pricing from 10 units. Start a quote.

Insurance & Standard of Care

Why insurers now ask where you stored the keys.

Some U.S. and UK insurers have begun denying or reducing claims on relay-attack theft when the owner cannot demonstrate reasonable signal-blocking storage. This is not yet universal — but the trend line is one direction, particularly on policies covering Range Rover, BMW M-series, AMG-line Mercedes, and Tesla.

Faraday storage is increasingly the documented standard of care. The argument from the insurer's side is straightforward: the threat is well-known, the defense is widely available, the cost ($129) is trivial relative to the asset value, and a buyer who has not deployed the defense has accepted a risk the insurer should not be asked to underwrite.

"Our underwriting questionnaire on Range Rover-line policies now includes a question about Faraday key storage. We are not yet declining policies on the answer, but we are pricing it." — Underwriter, U.S. high-value-vehicle insurer (off the record, 2026 industry briefing)

For HNW principals and family offices managing fleet portfolios, the documentation argument scales. A standardized REVIS-1 deployment across principal, family members, and core staff provides a paper-trail answer to the insurer's question for every covered vehicle in one purchase.

FAQ

What buyers ask before placing the order.

What is a relay attack on a smart car key?
A relay attack is a two-person theft technique that extends the radio signal between a parked car and the owner's key fob inside the house. One thief stands near the front door with a signal amplifier; the second stands at the car. The amplifier captures the LF wake-up signal from the car, relays it to the fob, captures the fob's response, and relays it back. The car unlocks and starts as if the real key were present. Total time: under 30 seconds. Equipment cost: under $200.
Does a Faraday bag stop a relay attack?
Yes — and it is the only physical solution that stops every variant. Faraday shielding mathematically blocks the radio signal from reaching the amplifier. With the key fob inside any of the three REVIS-1 chambers, no signal escapes, no signal can be amplified, no signal can be relayed. The car cannot be relay-attacked because there is nothing to relay.
Which car brands are most targeted by relay-attack theft?
Range Rover and Land Rover are the most-stolen vehicles in this category by absolute numbers (UK and U.S. insurance data). BMW, Mercedes-Benz, Tesla, Lexus, Audi, and Porsche all rank high. Toyota and Ford are increasingly targeted as more models adopt smart-key systems. The REVIS-1 has been verified against the relay frequencies used on every brand listed.
Will a Faraday bag also block the new phone-as-key (Bluetooth) systems?
Yes. The REVIS-1 blocks across 30 MHz – 10 GHz, which includes both the legacy LF key-fob bands (315/433/868/915 MHz) and the 2.4 GHz Bluetooth Low Energy band used by phone-as-key implementations (Tesla, BMW Digital Key, Apple CarKey on supported BMW/Hyundai/Kia/Genesis vehicles). Phone-as-key is in fact a higher-frequency target — same Faraday principle, same blocking.
Is a small Faraday key-fob pouch enough, or do I need a briefcase?
A single-key Faraday pouch ($20–$60) protects one fob and nothing else. The REVIS-1 protects the fob plus your phone (also a tracking and surveillance vector), your laptop, your tablet, your RFID-chipped wallet, and any other devices you carry. The same buyer purchasing a key-fob pouch usually has at least three other devices that need shielding. The briefcase consolidates all of them into one carry.
Can the REVIS-1 be left near my front door for daily key storage?
Yes. Many buyers use the REVIS-1 as their dedicated 'evening drop' bag — keys, wallet, phone, and laptop go into the bag when the principal arrives home. Bag stays at the entryway. Relay-attack thieves cannot complete the attack because the LF signal does not exit the bag. Pick the bag back up in the morning. The bag's executive form factor means it does not look like a security product to anyone visiting the home.
How quickly can a relay attack work?
Under 30 seconds, end to end, on a typical luxury vehicle. The thieves do not need to break a window, defeat an alarm, or pick a lock — the car opens normally and starts normally because, from the car's perspective, the real key is present. CCTV footage of relay-attack thefts shows the entire sequence: arrive, deploy amplifier, drive away. Most owners do not realize the car is gone until the next morning.
Are there legal liability implications for storing keys outside a Faraday container?
Some U.S. and UK insurers have begun denying or reducing claims on relay-attack theft when the owner cannot demonstrate reasonable signal-blocking storage. This is not yet universal, but the trend is clear — particularly on policies covering Range Rover, BMW M-series, AMG-line Mercedes, and Tesla. Faraday storage is increasingly the documented standard of care.
Does the REVIS-1 have other use cases beyond key fobs?
Yes — the REVIS-1 is a full executive Faraday briefcase. The three independently shielded chambers protect a MacBook, iPad, iPhone, key fob, and RFID wallet simultaneously. Key-fob protection is one of five primary use cases. See the Executive Faraday Briefcase brief for the full feature set, or the Best Faraday Briefcases 2026 guide for the cross-brand comparison.
Acquire

Make the relay attack impossible.

Three independently shielded chambers. 76–85 dB. Verified against every major brand's key-fob frequencies. $129. Free U.S. shipping. 30-day money-back guarantee.

Acquire Your Executive Guard — $129