Apple has officially entered the foldable smartphone market with the launch of its first foldable iPhone, the iPhone Duo, starting at $1,999. The device marks one of the company’s biggest iPhone design changes in years.

The iPhone Duo folds like a book and takes on a passport-like form when closed. It features a 5.4-inch outer display, while opening the device reveals a much larger 7.6-inch inner display.

Apple says the larger display is designed for watching content, gaming and multitasking. Both screens use the same aspect ratio, allowing a more consistent experience when moving between the folded and unfolded modes.

The device is powered by Apple’s new A20 Pro chip and features an advanced thermal-management system and dual-battery architecture. Storage options range from 256GB to 2TB.

Preorders for the iPhone Duo are scheduled to begin on October 16, with the device going on sale on October 23.