Apple's first foldable iPhone has failed another durability test. A new video from the YouTube channel AppleTrack shows the $1,999 iPhone Duo breaking down after exposure to sand and water and developing a deeper crease after repeated folding.

The video compares the iPhone Duo with Samsung's Galaxy Z Fold 8 in a series of stress tests covering frame strength, folding, display construction and outdoor exposure. It is the latest in a run of tests and owner reports that have raised questions about the device's durability less than a week after it went on sale.

Strong frame, weaker results elsewhere

The iPhone Duo started well. In the bend test, the reviewer found its frame felt sturdier than the Galaxy Z Fold 8's and better withstood maximum force.

Apple builds the Duo with a grade 5 titanium frame and a hinge made from a blend of titanium and aluminum. The company has promoted the build as one of the device's main strengths.

The results were less flattering after that.

Crease grows after 1,000 folds

In a 1,000-fold test, the iPhone Duo's inner display showed a more prominent crease than it had out of the box, according to the video.

The reviewer said the result undercut expectations that the display would stay pristine over time. A visible crease along the fold has long been one of the most common complaints about foldable phones.

Other testers have reported similar findings. Technology YouTuber Tim Pan folded an iPhone Duo 10,000 times and found no major problems beyond a more visible crease, BGR reported.

Removable display layer

The video also examined the inner display's nano-texture finish. Apple describes it........

© International Business Times