The one detail everyone missed in the Stranger Things Season 5 documentary

There’s a blink-and-you-miss-it moment in the 'One Last Adventure: The Making of Stranger Things 5' documentary that feels far more modern than anything happening in Hawkins.

Around halfway through the movie, Matt Duffer is sitting with a crew member, scrolling through a smartphone app.

Then, he points at the screen, half-laughing, half-wincing, and says he was already stressed when he woke up.

It’s a small, human moment, but for anyone familiar with wearable health tech, it feels instantly recognisable. The ring on his finger does too.

The geometry of stress

Throughout the documentary, Duffer wears a thick, matte-black band on his index finger.

He was also spotted wearing the same ring during the Hollywood Reporter Directors in Focus event on 12 December 2025.

It’s minimal, logo-free and visually identical to several current smart rings, including darker versions of the Oura Ring 4 and Ultrahuman's Ring Air, devices I’ve previously reviewed on T3.

And while there’s no confirmation that it is a smart ring, the context suddenly makes the theory hard to ignore.

One of Oura's most well-known features is its stress and readiness analysis, and its habit of bluntly telling you when your body is already under pressure before your brain catches up.

In fact, Oura is notorious for telling users they are stressed, which is why Matt's quick scene with the crew member made me instantly think he's wearing the Ring 4.

Despite my (and my wife's) best efforts to identify the ring, which appears in quite a few scenes in the documentary, it's impossible to tell whether it's even a smart wearable or just a tungsten ring with no smart features whatsoever.

The reference to stress scores and a smartphone app makes a strong case for smart rings, though.

When Hollywood measures itself

Matt Duffer isn't the only person working in showbiz who wears a smart ring.

Celebrities who were spotted with a finger wearable before include Prince Harry, Jennifer Aniston, Gwyneth Paltrow and Chris Hemsworth.

For all I know, someone from the above list recommended Duffer the ring, although given that smart ring shipments increased significantly last year (according to Bloomberg), it's possible that Matt, like the rest of us, came across a review and fancied trying it himself.

Given how gargantuan the process of making Season 5 of Stranger Things has been, I'm not surprised the writer-director wanted a smart wearable to label his stress levels.

One Last Adventure: The Making of Stranger Things 5 is available to watch now on Netflix.