iPhone Duo Beats iPhone Air as Apple's Thinnest iPhone, But Only When Open

The new foldable iPhone Duo is the "thinnest iPhone ever," according to Apple. When unfolded, the device is 5.2mm thick, making it 0.4mm thinner than the 5.6mm iPhone Air . Rumors suggested it could be as thin as 4.5mm when unfolded, similar to Samsung's Galaxy Z Fold8, but it didn't end up that thin.