Designs for two foldable iPhones have passed durability tests, according to reports picked up by TechRadar. Apple has also been granted a patent for hinge-mechanism.

As per United Daily News, these prototypes are just phone shells, which we’re assuming include the casings and the displays but not the various internal components. They’ve reportedly been tested out in China, at a factory run by Apple’s regular supplier Foxconn. One prototype is said to use a clamshell form factor, like the Samsung Galaxy Z Flip or the Motorola Razr. When opened up, the phone has one single and unbroken display, and then the top half folds down over the bottom half. Meanwhile, a new patent filing has been published, showing the hinge mechanism that Apple might be using on one of its foldable iPhone designs. It would actually enable the phone to fold both ways, inwards (like the Galaxy Z Fold 2) and outwards (like the Huawei Mate Xs).