tl;dr: Apple's iPhone Duo is its first foldable iPhone, featuring a 7.6-inch inner Super Retina XDR display (50% larger than iPhone 18 Pro Max), a 5.4-inch outer display, an under-display FaceTime camera, and a titanium frame with IP68 rating. It's powered by the A20 Pro chip, uses Touch ID in the side button, is eSIM-only, offers up to 31 hours of video playback, and supports Apple Pencil. Launching October 23, 2026, with new foldable-specific features like Duo Preview, Smart Take, and Duo FaceTime.