The iPhone Duo uses Super Retina XDR displays on both sides, with ProMotion and Always-On support. Apple rates peak outdoor brightness at 3,000 nits for both screens. A nano-texture finish on the inner panel reduces glare and makes the fold crease less visible, according to Apple. Grade 5 titanium forms the enclosure, while the precision hinge uses more than 100 components. Apple also gives the iPhone Duo an IP68 rating for water and dust resistance.