The iPhone Duo's foldable design resets the accessory market. According to Engadget, Apple's dimensional drawings show that older fitted accessories, particularly cases, will not fit the device, which measures 164.6 by 117.8 by 5.2 mm unfolded and 84.1 by 117.8 by 11.3 mm folded. Traditional tempered glass screen protectors are also problematic because they crack when the phone is snapped shut.
Some accessories carry over. USB-C peripherals and most wireless chargers continue to work, and existing MagSafe and Qi2 chargers generally function. However, MagSafe accessories built for longer iPhones may overlap or hang off the Duo's frame, so makers will need new designs for wallets and batteries. Mechanical car mounts may work only if their grips can accommodate the new dimensions.
Accessory makers are already responding. ESR's vegan leather magnetic case protects the hinge and includes a movable kickstand that doubles as a lens protector. Mous offers a thin aramid case that adds just 1.7 mm to the folded thickness but lacks hinge protection. Spigen's cases use the folding mechanism as a stand, with a more robust Armor option. For screen protection, flexible TPU or PET film protectors are recommended over glass.
For businesses, the iPhone Duo represents both a challenge and an opportunity. Apple's curated store lists approved third-party accessories, but at a premium. The new dimensions encourage manufacturers to innovate, and Apple plans a future software update to enable USB-C Apple Pencil support, avoiding the need for an extra high-power charging coil in the phone itself.