Apple has entered the foldable smartphone market with the iPhone Duo, putting particular emphasis on reducing one of the category’s most persistent problems, the visible display crease.

The device opens to reveal a 7.6-inch Super Retina XDR inner display, while the outside carries a smaller 5.4-inch screen. Both support ProMotion, Always-On functionality and outdoor brightness of up to 3,000 nits. Apple also plans to add support for the USB-C Apple Pencil later this year.

To make the centre crease less obvious, Apple has applied a nano-textured finish to the inner display to reduce reflections. Beneath the surface, the folding panel uses reinforced layers that include high-strength glass, a titanium plate and custom adhesives designed to allow slight movement as the screen bends.

Apple also says the polymer layer protecting the display is up to 40 per cent stiffer than materials commonly used in competing foldables.

Early hands-on impressions suggest the crease is still visible under some lighting conditions, but is considerably less distracting than on many existing folding phones.

Apple iPhone Duo 256GB (Star White)

Durability remains a bigger unanswered question.

Apple has equipped the iPhone Duo with a Grade 5 titanium frame, Ceramic Shield protection, an IP68 rating and a hinge made from more than 100 components. The company also says the internal structure has been reinforced for repeated folding.

However, Apple has not disclosed how many folding cycles the device has been tested or rated to withstand.

That leaves uncertainty over how the inner display, polymer surface and crease could change after months or years of repeated opening and closing.

The iPhone Duo starts at $3,499 at JB Hi-Fi.

For a first-generation foldable, Apple appears to have made significant progress in disguising the crease. The longer-term test will be whether that appearance and the hinge mechanism hold up after thousands of folds.