Foldable Phones CT Scanned: iPhone Duo, Pura X Max, Razr

Une photo de l'article avant la transition vers l'affichage de la tomodensitométrie.

iPhone Duo

Apple, 2026

The Duo is a 5.4-inch phone that folds open to reveal a 7.6-inch screen. Apple says the hinge was specially designed to hold it partly open, like a small laptop. The hinge is wrapped in a 3D-printed titanium cover. The Duo is the only phone in this group rated to IP68 for dust and water protection—an important detail to keep in mind as we compare it to the other phones.

Each side of the Duo has its own battery. iFixit found capacities of 7.5 Wh on the right side and 11.6 Wh on the left. The logic board sits on the right side, snuggled between one of the batteries and the main cameras. Only one half of the phone has a USB-C port, so the other battery charges through a very thin accordion-folded cable that passes through a gap in the hinge.

The hinge is two modules, one at each end of the fold, joined by a thin span. The side plates lie flat when the phone is open, then swing down at a 90 degree angle when it shuts. According to iFixit, each module holds a chain of linked metal joints, gears that keep the joints moving together, and springs that help the hinge hold a position and reduce the force it takes to bend the screen. Those springs and gears are what let the Duo stay partially open.

The center of the hinge is a complex intersection where the display cable crosses from one half to the other and several parts meet under the screen. Some early owners have reported display damage along the fold, and iFixit, comparing their photos with a hinge model built partly from CT scans, found that damage clusters near the hinge’s center support. The cause hasn’t been confirmed yet, but Apple is offering replacement units.

When closed the two halves sit flat against each other, with a thin, even gap running almost the whole way across. Right at the hinge, the gap opens into a rounded pocket. This pocket is the space inside the screen’s bend. The phone folds flat, but the screen inside it stays gently curved to reduce strain.

Pura X Max

Huawei, 2026

The Pura X Max has a similar shape and function to the Duo. Launched in China on April 20, starting at RMB 10,999 (about $1,650), it has a 5.4-inch outer screen and a 7.7-inch inner one, almost the same proportions as Apple’s foldable. It’s rated to IP58 for dust, one step below the Duo.

The hinge looks similar to the Duo’s: two mirror-image modules, one near each end of the fold, joined by a long, thin span. Huawei calls it the Basalt Water Drop Hinge and says its core components are steel.

The top plate is fastened down with a row of screws, with linkage plates and arms underneath. Coil springs run inside it, parallel to the fold axis just like the Duo.

This is where the name comes from. The two halves fold flat with a thin gap between them, then the inner layers swing apart into a rounded loop and wrap around at the spine. This is the water drop. The shape eases stress on the flexible OLED and its ultra-thin glass. Same solve as the Duo.

The battery configuration also mirrors the Duo. iFixit’s teardown puts the cells at 19.73 Wh combined. The Duo’s two cells add up to 19.1 Wh, which leaves these two phones nearly matched on battery capacity.

Razr 2026

Motorola, 2026

Not all folding phones are designed to open like a book. The Razr folds hamburger-style, the way flip phones always have, and sells for $799, less than half of the Duo’s price. Motorola describes this year’s hinge as titanium-reinforced. The phone is rated IP48, the lowest dust rating of the three.

There shouldn’t be any surprise here for the hinge as it follows the same general design: two mirror-image modules at either end of the fold. Like the others, a thin span connects them across the middle, but there’s one component that’s missing. This doesn’t have the long supports that extend out from the Duo’s and Pura X Max’s hinges when they’re open. The Razr’s side plates stay tucked close to each module.

Each module lines up the same parts: two coil springs side by side, a short row of gears, and a square block at the outer end with recesses radiating from a central hole, all held over a lower plate by three screws.

Close the Razr and the screen makes the same teardrop shape as the other two. The halves sit flat against each other while at the hinge, the inner layers drop into a rounded loop.

This shape has a history with the Razr, originating with the first Razr foldable handset in 2020.

Apple and Huawei went wide while Motorola kept the classic flip phone inspired fold. Inside, though, they have a lot in common. All three hinges have a similar design built around springs, and all three screens close into the same teardrop design Motorola was already using in 2020. The geometry of folding phones seems settled.

However, keeping grit out of the mechanism is an ongoing challenge. In iFixit’s powder test, enough dust reached the Duo’s hinge to make it crunch, even though the Duo is the only one of the three rated dust-tight. The same teardown notes that IP ratings cover a phone’s enclosure, which doesn’t appear to include the hinge.