For a long time the first foldable i Phone was rumored to be called i Phone Ultra, but Apple actually went with i Phone Duo. Bloomberg’s Mark Gurman has an intriguing theory: Apple is planning multiple foldable i Phones, including a bigger i Phone Duo Max, a smaller i Phone Duo mini, and an entry-level i Phone Duo SE. These suffixes work much better with Duo than with Ultra—just imagine an i Phone Ultra mini or i Phone Ultra Max.

The fact that Duo is three letters long, like Air and Pro, was also apparently part of the decision, and the word easily conveys the device's dual-screen nature. Whether Microsoft's Surface Duo was considered is still unknown.

Gurman thinks that, “by early next year,” the i Phone Duo will become “the predominant foldable phone on the market,” with demand “so intense that people will scalp the device for sale overseas, e Bay prices will soar, and supply shortages will reach extreme levels.” He also says it could turn foldables into the main form of mobile computing and push the industry to dramatically increase investment.