Apple on Wednesday unveiled the iPhone Duo, the company’s first-ever foldable iPhone, marking one of the most dramatic changes to the iconic smartphone since its introduction nearly two decades ago.

The new device combines a conventional 5.4-inch outer screen with a large 7.6-inch flexible display that appears when the phone is unfolded. Apple says the iPhone Duo is the thinnest iPhone it has ever produced when fully open and features the largest display ever offered on an iPhone.

The iPhone Duo will not come cheap. Prices begin at $1,999 in the United States for 256GB of storage, with 512GB, 1TB and 2TB configurations also available. The top-of-the-line 2TB version will cost $3,199. Preorders are scheduled to open October 16, with the phone going on sale October 23 in the United States and more than 70 other countries and regions.

The phone will initially be offered in two colors, Star White and Night Sky.

Apple designed the two halves of the Duo so that they form a continuous frame, with the inner and outer displays sharing the same aspect ratio. The idea is to allow content to transition naturally from the smaller exterior screen to the much larger interior display when the device is opened.

The 5.4-inch outer Super Retina XDR display provides roughly 90% of the screen area of the iPhone 18 Pro. Opening the Duo reveals a 7.6-inch Super Retina XDR display that Apple says is 50% larger than the screen on the iPhone 18 Pro Max.

Both screens feature ProMotion, Always-On display technology and peak outdoor brightness of 3,000 nits. Apple also announced that Apple Pencil support will be added to both displays later this year.

One of the biggest engineering challenges with foldable phones has been the visible crease where the screen bends. Apple says it developed a special nano-textured surface for the Duo that reduces reflections while helping minimize the appearance of the crease.

Underneath the flexible screen is an elaborate multilayer structure. Apple says custom adhesives allow the layers to move against one another as the device folds, while a titanium plate and other support structures provide stiffness and durability.

The folding mechanism itself contains more than 100 precision components. The hinge is designed both to support the center of the display when the Duo is completely open and to provide a controlled opening and closing motion. Magnets help keep the phone securely shut when folded.

The exterior frame is made from polished Grade 5 titanium. Ceramic Shield protects the rear, while Ceramic Shield 2 covers the outer display. Despite the moving hinge and foldable screen, Apple says the Duo carries an IP68 rating for water and dust resistance.

Unlike Apple’s other flagship iPhones, the Duo uses Touch ID integrated into its side button. Users can also unlock the phone through a paired Apple Watch.

Apple has extensively modified iOS 27 to take advantage of the unusual form factor. Controls have been moved toward the sides of the screen so they remain within reach, while the Home Screen dock and Dynamic Island have been redesigned for the larger display.

The software automatically responds as the phone is folded, opened, rotated or propped up. Content can move away from the crease when the phone is partially folded, while apps can transition between the outside and inside displays without forcing users to start over.

Perhaps the biggest change is multitasking. For the first time on an iPhone, users can run two applications side by side using Split View. They can also open two windows of the same app — such as two Safari windows — and save frequently used pairs of applications so they can be reopened together.

Several third-party developers have already optimized their apps for the new design. Apple says Netflix, Zoom and Slack are among the apps taking advantage of the folding screen.

The Duo also introduces an expanded StandBy mode. When placed on a surface, the foldable phone can function as a bedside clock, photo frame or information display, with calendar, weather, music and other widgets available.

Under the hood, the iPhone Duo is powered by Apple’s new A20 Pro chip, the same processor used in the iPhone 18 Pro models. Apple says the chip is manufactured using 2-nanometer technology and provides up to 35% better sustained performance than the iPhone 17 Pro when paired with the Duo’s new thermal-management system.

The company has also fitted the phone with its new C2 cellular modem, which supports 5G mmWave in the United States, along with an Apple-designed N1 networking chip supporting Wi-Fi 7, Bluetooth 6 and Thread. The iPhone Duo will be eSIM-only worldwide.

The phone includes two batteries, one housed in each half of the device, but software manages them as a single power source.

Apple rates the Duo for up to 31 hours of video playback using the inner display and up to 44 hours using the exterior screen. When both screens are used equally, Apple says the phone can provide up to 24 hours of use on a charge. Fast charging can bring the battery to approximately 50% in about 20 minutes.

The Duo also incorporates a redesigned camera system built around a 48-megapixel Fusion main camera and a 48-megapixel Fusion Ultra Wide camera, the latter shared with the iPhone 18 Pro lineup.

Because the phone can remain standing while partially folded, users can position it on a surface without a tripod for photos, FaceTime calls and time-lapse videos. The main camera supports 4K video at up to 120 frames per second in Dolby Vision, while time-lapse video can be recorded in 4K Dolby Vision HDR.

The outer screen contains a 12-megapixel Center Stage front camera. A separate FaceTime camera is concealed beneath the inner display, leaving the large screen uninterrupted when the camera is not being used.

The unusual two-screen configuration also gives Apple several new photography options. Users can take high-quality selfies with the rear cameras while previewing themselves on the outer display. Another feature, Duo Preview, allows the person being photographed to see the live image on the outside screen.

A feature called Smart Take uses on-device artificial intelligence to monitor a group and automatically snap a picture when the subjects are ready, eliminating the need for someone to race into position before a timer expires. Kid Cue can display animations on the outer screen to encourage children to look toward the camera.

The Duo can also capture the front and rear views simultaneously. A new Duo FaceTime mode even allows someone standing with the phone’s owner to participate in the same FaceTime conversation using the exterior screen.

The iPhone Duo will also be one of Apple’s showcase devices for its expanding artificial-intelligence features. It supports Apple Intelligence and the new Siri AI experience, with the larger screen designed to allow users to interact with Siri while simultaneously viewing other content.

Apple is introducing two dedicated accessories alongside the phone: a two-piece protective iPhone Duo Case and a Duo Folio featuring a built-in kickstand. The case will cost $79, while the Folio will sell for $129.

The iPhone Duo will ship with iOS 27.1. Customers in the first wave of more than 70 countries and regions will be able to preorder the phone beginning at 5 a.m. Pacific Time on Friday, October 16, before its official release one week later, on October 23. Another 28 countries and regions will receive the device on October 30.

With the Duo, Apple is entering a foldable smartphone market years after several of its major competitors, but it is doing so with an unmistakably Apple approach: a premium titanium design, extensive hardware-software integration, and an equally premium price tag.

At $1,999 for the least expensive version and as much as $3,199 for maximum storage, the iPhone Duo is positioned not simply as another iPhone model but as a new ultra-high-end category within Apple’s smartphone lineup.