The rumored iPhone 17 Air will have a titanium frame, according to Apple analyst Jeff Pu.

In an investor note with equity research firm GF Securities this week, Pu also said the iPhone 17, iPhone 17 Pro, and iPhone 17 Pro Max will have aluminum frames, so the iPhone 17 Air will apparently be the only new model to use titanium.

It is unclear why the iPhone 17 Air would have a titanium frame, as aluminum is lighter than titanium, which would be fitting for the device's rumored ultra-thin and lightweight design. Titanium is generally stronger than aluminum, however, so perhaps the material is necessary to ensure that the iPhone 17 Air's thin chassis is durable.

Last year, another Apple analyst Ming-Chi Kuo said the iPhone 17 Air's frame would use both titanium and aluminum, so there could be a mix of both materials. Apple surely has its reasons, and it may discuss them during its iPhone 17 event in September.

Since the iPhone X in 2017, all of Apple's highest-end iPhone models have featured either stainless steel or titanium frames, so the return to an aluminum frame for the iPhone 17 Pro models this year would be a notable change.

Here is what Pu expects:

• iPhone 17: Aluminum frame
• iPhone 17 Air: Titanium frame
• iPhone 17 Pro: Aluminum frame
• iPhone 17 Pro Max: Aluminum frame

Here are the materials used for the iPhone 16 series:

• iPhone 16: Aluminum frame
• iPhone 16 Plus: Aluminum frame
• iPhone 16 Pro: Titanium frame
• iPhone 16 Pro Max: Titanium frame

Source: Macrumors