Foldable iPhone, pricier 18 Pro unveiled in Apple's first event under Ternus

Duo marked the biggest redesign of the iPhone line in years. The passport-shaped device opens into a 7.6-inch display and features a 5.4-inch outer screen. The large display allows users to keep two apps open at the same time.

The device is powered by Apple's A20 Pro chip, built on a 2-nanometer process. Apple said the chip, paired with a vapor-chamber cooling system, is designed to improve on-device AI performance, graphics processing and battery efficiency. Duo also includes Apple's latest C2 modem.

Duo supports Apple Pencil and uses Touch ID integrated into the side button. Apple said it is the thinnest iPhone when open. Pricing starts at $1,999, about $100 more than Samsung's Galaxy Z Fold8 and Google's Pixel 11 Pro Fold at comparable base storage levels.

Duo offers up to 2 terabytes of storage, a capacity not available on the rival foldable models. Pre-orders begin October 16 and the device goes on sale October 23.