How NFC wristbands work.

A tap takes about a second. Here’s what goes on in it.

1. The phone’s NFC reader puts out a weak radio field, only a few centimetres deep.
2. The chip in the band has no battery. That field powers it for a moment.
3. The chip answers with what’s stored on it. On an NFC wristband made for sharing contacts, that’s a single web link, saved in the standard NFC format phones already understand.
4. The phone opens the link in its browser, the same way it opens any website.

Because the range is so short, a tap only happens when someone deliberately holds a phone against your wrist. It doesn’t work from across a room, and it doesn’t work through a pocket at a distance.

No, and neither does the person tapping you. iPhones and Android phones read NFC web links on their own and open them in the browser. Works with most NFC phones (recent iPhones and most NFC Android phones), no app.

What they see is a normal web page: your name, your links and a Save contact button. You manage that page from your dashboard in the browser too, so there’s nothing to download on either side.

Hold the top of the back, near the camera to the band. Not the screen: the iPhone’s NFC reader sits at the top of the phone, on the back.

• Have the screen on. Recent iPhones read NFC tags in the background whenever the screen is awake.
• A notification slides down from the top of the screen. Tap it and the page opens.
• If nothing happens, close the camera or Wallet (the phone won’t read a tag while they’re open) and try again.

Some older iPhones don’t read tags in the background. If a phone can’t read the band at all, the QR pocket card in the box opens the same Larp page with the camera.

Hold the middle of the back to the band. That’s where most Android phones keep their NFC antenna.

• NFC has to be on. It usually is, because tap-to-pay uses it. If it isn’t, search “NFC” in Settings and switch it on.
• Have the screen on and unlocked. The page opens in the phone’s browser.
• If it doesn’t read, slide the phone slowly over the band. The spot that reads is small.

Hold still for about a second, with the phone flat against the band. Moving too fast is the most common reason a tap doesn’t read.

• For the Larp side, the phone goes on the raised face on the outside of your wrist.
• For the Alt side, flip your wrist. The Alt chip is a thin NFC tag sealed on the inside of the band's bottom, against your wrist, so you won't see it from outside. Flip your wrist and tap the bottom of the band.
• Thick cases, metal cases and card wallets on the back of a phone can block the read. So can some older phones.

Just a link to your page. Not your name, not your number. Your details live on the page, so you can edit them any time in your dashboard and the band keeps working: the next tap shows the new version.

We write and lock both chips before a band ships, so nobody can reprogram yours to point somewhere else. Lost it? Switch the band off from your dashboard, and taps stop showing your page until you switch it back on.

When someone taps you, you see the time and an approximate city, never their exact location or who they are. They only share their details with you if they choose to send theirs back.

No. A phone has to be within a few centimetres of the chip, so in practice it means holding a phone against your wrist. And anyone who did that would get exactly what a normal tap gives: the page on that side.

That’s also why the Alt side sits on the inside of your wrist, against your skin. Reaching it takes you flipping your wrist on purpose. The thinking behind that split is in keep your number private, and the whole band is explained on the NFC wristband page.