RFID protection works like a tiny Faraday cage. Tap-to-pay cards, most transit cards and e-passports answer readers at 13.56 MHz. An Alpine Rivers® sleeve with verified 13.56 MHz shielding wraps the card in conductive layers, so it stays quiet when a reader comes close, then taps normally once out. The reader demo is at the end of this page.
What contactless cards actually do
A contactless card contains a small antenna and a chip. When the card is held near a reader, the reader emits a radio field. The antenna picks up that field, powers the chip, and transmits the data the reader requests. No physical contact. No keystrokes. No PIN at low values.
The standard frequency for most consumer contactless cards is 13.56 MHz. That includes Visa payWave, Mastercard PayPass, American Express ExpressPay, most modern hotel keycards, and the chip layer of e-passports.
What skimming looks like in practice
A skimmer is any device that emits the right radio field, prompts the card to respond, and captures the response. Skimmers can be:
- Hand-held units the size of a phone, walked past a bag or a back pocket on public transit
- Hidden inside a clipboard, a backpack, or a coat sleeve
- Mounted inside legitimate-looking payment terminals or building entry points
The card does not need to leave your pocket. It does not need to be held up. Range is short, but in a crowded space, short is enough.
How a Faraday cage stops the read
A Faraday cage is a continuous conductive enclosure. When a radio signal hits the outside of the cage, currents in the conductive layer cancel the field inside. The field that reaches the card is too weak to power its chip. It cannot respond to a signal it cannot detect.
Alpine Rivers® sleeves, money belts and neck wallets wrap cards in a multi-layer shielded barrier built on this principle. The card stays usable when you take it out to tap, and quiet while it is inside.
What Alpine Rivers® products do
- Sleeves wrap a single card front and back, with a snug opening
- Money belts and neck wallets enclose multiple cards inside a shielded compartment, with the shielding integrated into the wall of the compartment, not just a flap
No layered barrier is absolute, and we claim only what we can show: verified 13.56 MHz shielding while the cards are inside.
Read about the specific frequency and why it matters in Why 13.56 MHz Is the Only Frequency That Matters.
Frequently asked questions
How does an RFID blocking sleeve work?
It works like a small Faraday cage. The sleeve wraps the card in conductive layers, and when a reader's 13.56 MHz field reaches them, the energy is absorbed and spread out before it can power the card's chip. The card stays quiet until you take it out.
Can I still pay with a card that lives in an RFID sleeve?
Yes. Slide the card out and tap as usual; it works just as before. While it is inside a sleeve with verified 13.56 MHz shielding, the terminal should not register it, so take it out first.
Will an RFID sleeve wear out or damage my card?
No. The sleeve is passive, with no battery, no power and no moving parts. It does not alter the card or its chip, and storing a card in it adds no wear beyond normal handling. Replace the sleeve itself if its liner tears.
Do phone and watch wallets need RFID protection?
Not from a card sleeve. Phone and watch wallets pay from the device, and most ask for a face, fingerprint or passcode before a payment. Sleeves are for the physical cards you carry, and they do not affect your phone wallet.
Does an RFID sleeve protect a card while I am paying with it?
No. A sleeve shields a card only while the card is inside it. Once you take a card out to tap, it behaves like any contactless card, so keep the cards you are not using in their sleeves and put the card back after you pay.
Go deeper
- Do RFID sleeves work? Ten live card reader tests
- Does RFID blocking actually work? The science at 13.56 MHz
- Our 2016 approval (GSA APL 1424) and its honest status today
- What RFID skimming actually looks like in 2026
- Choosing a sleeve for PIV and CAC cards
- RFID sleeve FAQ: payments, passports and PIV cards
Shop: RFID blocking sleeves, money belts and neck wallets.