Most of the iPhone Duo’s specification sheet is shared with the iPhone 18 Pro Max, down to the chip, the radios and the water rating. Seven hardware entries on it are not, and they are the only places where Apple’s $1,999 foldable is genuinely alone in the lineup: two displays, a nano-texture finish, Touch ID, a camera under the screen, two batteries, Apple Pencil support and a titanium hinge.
Everything else about the Duo either matches another iPhone or falls short of one. Sorting the sheet this way is the quickest route to what the fold actually adds.
Key facts: the seven Duo-only hardware entries
| Feature | What Apple publishes |
|---|---|
| Two displays | 7.6-inch folding inner display at 1878 by 2670 and 430 ppi, 5.4-inch cover display at 1398 by 2034 and 460 ppi |
| Nano-texture finish | A custom nano-texture finish on the inner display, which Apple says reduces glare and minimizes the visible crease |
| Touch ID | Touch ID in the side button, open or closed, multiple fingers, unlock with Apple Watch. No Face ID |
| Under-display camera | An inner FaceTime camera beneath the folding display, f/1.8, 1080p at 30 or 60 fps, with Center Stage |
| Dual battery | One cell per side, rated separately: up to 44 hours of video on the cover display, up to 31 hours on the inner display |
| Apple Pencil | Apple Pencil (USB-C) on both displays, support arriving later in 2026 |
| Titanium hinge | Grade 5 titanium frame and hinge cover, more than 100 components, custom adhesives for flex relief |
Two displays, and a finish Apple gives no other iPhone
Both Duo screens are Super Retina XDR OLED panels with ProMotion to 120Hz, Always-On, 1000 nits typical brightness and 3000 nits peak outdoor brightness, so neither is a cut-down secondary display on paper. The inner one is the one Apple calls the largest display of any iPhone.
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The nano-texture finish is the detail with no equivalent anywhere else in the iPhone range. Apple applies it to the inner display only and gives it two jobs, cutting glare and minimizing the crease, over a cover made from a custom polymer Apple says is 40 percent stiffer than the industry standard, above high-strength glass layers and under a scratch-resistant coating.
Touch ID, a camera under the screen and two batteries
Touch ID in the side button is the Duo’s only biometric. Apple says it works with the phone open or closed, stores multiple fingers and supports unlocking with an Apple Watch. Every other iPhone Apple announced this month uses Face ID.
The inner camera sits under the folding display at f/1.8 and records 1080p at 30 or 60 fps, well short of the 4K the cover camera manages. The battery is split into one cell per side, which is why the Duo is the only iPhone with two video-playback ratings rather than one, and why Apple’s 24-hour typical-use figure comes with a stated assumption of equal inner and cover display use.
The hinge, and a Pencil that arrives later
Apple describes the hinge in more detail than any other part of the phone: Grade 5 titanium with a mirror-polished finish, a cover 3D printed from 100 percent recycled titanium, more than 100 components, and custom adhesives for flex relief. The enclosure is 85 percent recycled titanium and the phone carries 35 percent recycled content overall.
Apple Pencil (USB-C) is the other entry with no precedent on an iPhone. Apple says it works on both displays and that support arrives later in 2026, which means it is not a day-one feature on October 23. Two smaller lines are also Duo-only on the published sheets: DisplayPort output named on the USB-C port, and eSIM-only operation in every market rather than in 12 of them.
What the rest of the lineup has and the Duo does not
The exclusives run in both directions. Apple’s own sheets put the Duo behind the iPhone 18 Pro and Pro Max on five published lines, including the telephoto lens and the front camera, and its longest camera setting is a crop rather than a lens.
| What the rest of the lineup has | Where iPhone Duo lands |
|---|---|
| A 48MP 100 mm f/2.8 tetraprism telephoto on iPhone 18 Pro and Pro Max | No telephoto lens. A 12MP 2x crop at 52 mm |
| An 18MP Center Stage front camera at f/1.9 on iPhone 18 Pro, Pro Max, iPhone 17 and iPhone Air | 12MP at f/2.2 on the cover display |
| Face ID on every other new iPhone | Touch ID in the side button |
| In stores Friday, September 18 | Ships Friday, October 23, five weeks later |
| Four finishes on iPhone 18 Pro | Two, Night Sky and Star White |
What Apple has not said
Apple has published no fold-cycle rating for the hinge, no crease measurement, no battery capacities for either cell, and no Apple Pencil date beyond later in 2026. It has not said which Pencil features the displays support, or what the under-display camera gives up compared with a conventional one. Nobody outside Apple has used an iPhone Duo, so none of the seven entries above has been assessed in use. Our Duo against iPhone 18 Pro Max comparison covers the shared lines.
iPhone 18 Pro and iPhone 18 Pro Max pre-orders are due to open today, Saturday, September 12 at 5 a.m. PT, ahead of a Friday, September 18 release. iPhone Duo pre-orders open on Friday, October 16 and it ships on Friday, October 23.
