Apple sets preorder date for its ambitious and expensive iPhone Duo

Apple's ( AAPL ) foldable iPhone Duo is up for preorder on Friday, just days after the company's market cap topped $5 trillion for the second time .

Apple's most ambitious iPhone yet, the passport-sized Duo is also one of Apple's priciest smartphones to date.

Starting at $1,999, the Duo features a 5.4-inch front display and a 7.6-inch foldable inner screen, with a nano-texture finish that helps prevent glare while making the panel's center crease all but invisible.

The book-style foldable is a first for Apple, which has sat out the folding-phone market for years while rivals Samsung ( 005930.KS ) and Google ( GOOG , GOOGL ) have grabbed market share and iterated on their designs.

But Apple is notorious for allowing other companies to do the legwork in developing a new market only to swoop in and grab its own piece of the pie. That's exactly what the iPhone maker did with the AirPods and Apple Watch, which have become bestselling devices in their respective categories.

The iPhone Duo brings a number of new features to Apple's all-important product line, including the ability to run two apps side by side or two windows of the same app simultaneously.

Apps seamlessly transition from the front screen to the main display and back. You can also take advantage of the Duo's foldable design by positioning it like an open laptop on your desk, allowing you to view content on the top of the screen while navigating on the bottom half.

In Standing Mode, you can position the Duo like a tent on a flat surface to watch shows and movies, or use the phone as a high-powered clock for your nightstand.

Apple has also thrown in some extras on the camera front. If you unfold the phone and open the camera app, the front screen will provide your subject with a preview of your shot. The idea is to spare friends, couples, and everyone in between the awful experience of having someone take your picture, only to immediately look at the result and demand a redo.

The Duo gets ultra-wide-angle and wide-angle rear cameras, but no telephoto option. Up front, the phone gets Apple's Center Stage camera, which helps keep the user in view even if they move side to side.

There's also an under-display FaceTime camera hidden beneath the main folding screen.

Foldable phones are still a relatively niche market segment. According to market research firm IDC , manufacturers were projected to ship 1.25 billion units in 2025. Foldables were expected to make up just 20.6 million of those.

But the company says it anticipates foldable smartphones will account for roughly 10% of the market by 2029. It hit a major cumulative milestone in 2026 with total lifetime units set to surpass 100 million by the end of the year, according to Counterpoint Research's latest Foldable Smartphone Market Forecast .

Email Daniel Howley at dhowley@yahoofinance.com. Follow him on Twitter at @DanielHowley .