iPhone Duo review: Apple's first foldable dazzles but compromises

Build and handling

The Duo uses a grade 5 titanium frame, and the two halves line up with no mechanical play. The hinge, made of more than a hundred mechanical parts and magnets, moves smoothly, closes with a crisp click and holds any angle, so the phone can stand like a small laptop or an easel.

The weak point is weight. At 254 grams it is heavier than the iPhone 18 Pro Max (249 g) and far above the Galaxy Z Fold 8 (200 g). Closed, it is 11.3 mm thick and 117.8 mm tall, which makes it awkward in a trouser pocket, especially with the Folio case. One-handed opening is not easy.

Controls and software

The testers criticise several choices. The volume buttons sit on the top edge and are not swapped automatically when the orientation changes. The Action button is gone, while the Camera Control button stays, with its capacitive functions disabled by default as on the iPhone 18 Pro.

Face ID is replaced by Touch ID in the power button, a return to a sensor last used on the iPhone 8 in 2017. Both testers found it slow, and the left-handed one says it often fails to register. That tester also points out that menus and shortcuts on the outer screen are anchored to the right with no setting to switch sides, and that at 78 mm wide the phone is hard to use one-handed with the left thumb. Open, used with two hands, it is more comfortable.

There is also no telephoto lens. The back keeps the titanium and glass construction of the iPhone 16 Pro rather than the unibody design of the iPhone 18 Pro.

The verdict is mixed: the Duo shows Apple's craftsmanship and some smart ideas, but its weight, ergonomics and price make it a product for early adopters.