We just CT scanned 1,000 lithium-ion batteries from 10 brands to see how they compare inside.

The differences we found are enormous, and point to serious safety risks in off-brand batteries that can easily make their way into the supply chain. Here’s what we saw… 🧵 Can you spot the differences between these two batteries? One is a legitimate Samsung cell; the other is a counterfeit. It’s marked with a Samsung-style part number and feels well-made.

Last month @AnkerOfficial recalled over one million power banks due to an unspecified battery manufacturing issue. We CT scanned 3 recalled power banks and 2 that weren’t recalled to see what’s going on inside. Here’s what we found… Lithium-ion batteries must be manufactured to extremely tight tolerances. They’re made by winding thin films of positive electrode (cathode), negative electrode (anode), and separator into a tightly packed “jelly roll” that's sealed into a cylindrical can or rectangular pouch.

Do water filters actually do anything? We CT scanned several popular water filters before and after use to see what they’re able to keep out of your body. Here’s what we found… 🧵 These are before-and-after @lumafield scans of a Brita water filter; it’s filled with a blend of activated carbon and ion-exchange resin and claims to trap chlorine, sediment, and heavy metals like lead. The filter medium swells with use, and it also gets denser. How do we know?

This looks like an ordinary USB-C connector, but when we CT scan it, we find something sinister inside…🧵 Last year we CT scanned a top-of-the-line Thunderbolt 4 connector and were astonished to find a 10-layer PCB with lots of active electronics. A lot of people saw the scan and wondered whether malicious electronics could be hidden in a tiny USB connector.

https://x.com/JonBruner/status/1714696044356005949

We just announced a major breakthrough in X-ray CT technology at @lumafield: scans that take hours with conventional CT will now take seconds. Here's why that's important 🧵 A CT scan is the richest possible source of industrial inspection data: it gives you a full 3D model of your part, inside and out, along with relative density information. But it's always been too slow for use in high-volume production environments—until now.

Pens are made by the billion, require insane precision, and still work almost every time. We CT scanned a few common pen types to see what’s inside... 🧵 First up: a fountain pen 🖊️ These date back to the 10th century, but practical designs appeared in the 19th century. When the pen is tilted, gravity pulls ink from a cartridge to the nib. Capillary action pulls the ink through a slit in the nib, where it flows onto the page. Here are the 2D X-ray radiographs we captured of a fountain pen; we use software to reconstruct them into a 3D model (next tweet).

We CT scanned an Apple Vision Pro! We also scanned two Meta headsets. Here’s what we found inside, and what it says about the two companies’ approach to AR/VR and to hardware development in general. 🧵 Here are our industrial CT scans of the Meta Quest Pro and Meta Quest 3 headsets. If you want to explore these scans, head to . Now let’s see what we found… lumafield.com/article/apple-…

This is an industrial X-ray CT scan of a Luer activated valve—a tiny medical connector that costs just 75 cents but is remarkably complex. Let’s take a look at how it works… 🧵 Luer connectors are used to join medical tubing for fluid delivery—think tubes that hook into IV bags, or needles that fit onto the ends of syringes. Hospitals use thousands every day. They twist together with less than one turn and must be secure and completely leakproof.

We CT scanned a Stanley Quencher cup to look for the lead that’s supposedly inside. Here’s what we found, and what it says about how these cups are made… 🧵 These cups have been a viral sensation, increasing Stanley’s revenue 10X since 2019. But late last year, social media influencers discovered lead in the cups. Stanley confirmed the cups contain lead, but says the lead doesn’t contact the cup’s contents. So what’s going on?

This is a CT scan of Heinz’s new ketchup cap. It represents a $1.2 million engineering investment over 8 years. Here’s why it’s significant… 🧵 This is the previous Heinz cap design. CT scans like @lumafield’s capture density, shown here on a blue-red spectrum. There are three plastics in this cross-section. The bottle is PET, and the cap is unlabeled but likely polypropylene. Inside the cap is another material.

Guess that scan! This is an industrial CT scan of an everyday object, shown in cross section. Do you know what it is? @lumafield No one's guessed it yet! Here's a hint: this is a section along a different plane.

There are billions of Christmas tree lights in the world. We CT scanned a few and found that they’re much more complex and intricate than they seem. Let’s take a look… 💡🧵 This is a standard incandescent bulb from a string of holiday lights. It has a tiny tungsten filament just like a regular old bulb, but there’s something else in this image…

This is a CT scan of a Furby! 😱

We captured it for @bekathwia’s latest teardown video; let’s see what’s inside… 🧵 @bekathwia The Furby reacts to being patted on the head. Indeed, when we look inside it one of the most prominent features is a spring-loaded head-pat sensor.

(CT captures relative material density; we can strip away fur and plastic, isolating denser materials like steel and copper.)

The world is full of counterfeit Apple products. We CT scanned two fake AirPods and compared them to the real thing… 🧵 This is an authentic AirPod Pro (2nd Generation). It’s a marvel of miniaturization. Everything is packed into the curved enclosure efficiently with tightly integrated flexible PCBs.

Happy Halloween! Here's a CT scan of a pumpkin. Here's my favorite view, with the denser shell stripped away to show the pulp inside.

What’s inside Apple’s $129 Thunderbolt cable? We CT scanned one to find out, and compared it to some cheaper cables… 🧵 Turns out there’s a lot going on in this Thunderbolt 4 connector. There’s a very complex PCBA that appears to have two inductors. This cable can deliver 100W to the connected device, plus it has to power its own ICs.

Perhaps you've wondered what Doritos would look like in a CT scan. We did, so here's a clump of Cool Ranch Doritos, scanned through the bag. But there's more...🧵 We also put Cheetos and Ruffles in our industrial CT scanner, then had some extra fun with the scan data.

Here's a thread: generative artificial intelligence has made breathtaking gains in the last four years. For instance, these are images of imaginary bedrooms and imaginary album covers created by a neural network. (For more on this, and these examples, see: jebruner.com/2018/03/optimi…)