US tech giant Apple on Wednesday unveiled its first foldable smartphone, iPhone Duo, along with the iPhone 18 Pro lineup, new Apple Watch models and AirPods at a product launch event held at Apple Park, its headquarters in Cupertino, California.

The iPhone Duo features a 13.7-centimeter outer display that opens to reveal a 19.3 cm inner display, the largest ever on an iPhone, according to Apple. When closed, the device is roughly the size and shape of a passport, while unfolded, it is Apple's thinnest iPhone to date.

The iPhone Duo is made of Grade 5 titanium and features a precision hinge. Its inner and outer Super Retina XDR displays have the same aspect ratio, so content scales proportionally as users switch between the two screens.

The hinge includes more than 100 components to precisely control opening and closing and support the center of the display. The inner display also uses a nano-textured cover layer and high-strength glass above and below the folding display panel to reduce crease visibility and improve durability, according to Apple.

The device is powered by Apple's new A20 Pro chip, built on a 2-nanometer process. The chip features a six-core CPU, a seven-core GPU and a Dual 16-core Neural Engine designed to support on-device artificial intelligence (AI) workloads.

The foldable phone also features a dual-battery architecture and a custom vapor chamber for thermal management. It offers up to 31 hours of video playback on the inner display and 44 hours on the outer display, according to Apple.

Apple redesigned parts of iOS 27 to accommodate the foldable form factor. A new Split View feature allows users to run two apps side by side on an iPhone for the first time, while also enabling them to open two windows of the same app.

The iPhone Duo comes with Apple Intelligence and Siri AI.

Apple's entry comes as competition in the foldable smartphone market intensifies. Huawei and Xiaomi unveiled new foldable models in China on September 7, just days before Apple's launch, highlighting the increasingly competitive market Apple is entering.

Apple also unveiled the iPhone 18 Pro and iPhone 18 Pro Max. Both models are powered by the A20 Pro chip and feature a new 48-megapixel Fusion Main camera with a variable aperture, along with improvements in battery life and sustained performance.

Apple also introduced Apple Watch Series 12 and Apple Watch Ultra 4, featuring a new Health Sensing System and the S11 chip. It also unveiled AirPods 5, bringing active noise cancellation to its entry-level AirPods lineup.

The event marked the first major Apple product launch led by John Ternus since he took over as the company's CEO. The introduction of the iPhone Duo marks Apple's entry into the foldable smartphone market.