Apple has unveiled its first foldable device, the iPhone Duo, but the name and concept both have a long history that predates the launch. The Verge notes that "Duo" has been used repeatedly across the tech industry for decades, spanning gaming consoles, laptops, chargers and rival foldable phones, meaning Apple's new device is far from breaking new ground either in folding-screen technology or in branding.

Notable prior Duos include:
– NEC TurboDuo (1993) – a hybrid games console combining the TurboGrafx-16 and TurboGrafx-CD, discontinued in 1995.
– Google Duo (2016–2022) – a video-calling app later folded into Google Meet.
– Apple PowerBook Duo (1992) – an ultraportable laptop, Apple's actual first "Duo" device.
– Apple MagSafe Duo (2020–2023) – a dual wireless charger for iPhone and Apple Watch.
– Microsoft Surface Duo (2020) – a dual-screen phone with a visible hinge rather than a flexible display, which struggled commercially despite a 2021 sequel.
– Asus ROG Zephyrus Duo – a dual-screen gaming laptop (details cut off in source text).