This smart ring lets you buy stuff with your finger, no phone required

Kerv, a new smart ring now available in the UK, promises to bring purchasing power directly to your finger.

Smart devices with instant purchasing capabilities aren't exactly revolutionary—people have used their phones to buy stuff through services like Apple Pay for a few years now—but Kerv offers a new twist. The ring purportedly works without a smartphone connection, giving its users an untethered experience using near field communication (NFC) technology.

Kerv works on MasterCard's payment network. Users must register for a Kerv Virtual Prepaid MasterCard account, but once the ring is connected, it should work anywhere in the world that accepts the company's contactless payments.

The makers of Kerv claim the device is the first smart ring in the world with purchasing capabilities, but it's facing challenges from another UK-based smart ring maker, NFC Ring, which also uses NFC tech to make payments. NFC Ring contends Kerv used NFC's intellectual property in its design—a claim Kerv denies, of course.

The team behind the NFC Ring has demonstrated its purchasing capabilities before, most notably through its partnership with Visa. The company debuted the tech in 2015 and later sent rings to "top athletes" for use in the Olympic Village during the 2016 Rio Olympics. NFC Rings are currently available for pre-order in the EU but will ship worldwide. They require a connected Android device to work, unlike Kerv.

Philip Campbell, Kerv's founder, acknowledged the dispute between the two ring makers via email. He said the most recent legal challenge is taking place in the U.S. market, where Kerv currently doesn't have a presence or plans to expand.

Campbell is confident the controversy won't be an issue for Kerv going forward—but it might be something to keep an eye on if you're looking to pick up one of the wearables in the future.