As questions mounted Thursday about the structural integrity of the iPhone 6 and in particular the 6 Plus, an Apple spokesperson reached out to CNBC to explain in some detail how the company designs and tests iPhones for durability, and to say that through Wednesday, just nine customers had contacted Apple saying their phones had bent.
It's not clear if one of those complaints came from Wired reviewer Mat Honan, who wrote in a generally positive review that his 6 Plus had bent during his review period, though he didn't remember sitting on it.
The iPhone 6 and 6 Plus "feature a precision engineered unibody enclosure constructed from machining a custom grade of 6000 series anodized aluminum, which is tempered for extra strength. They also feature stainless steel and titanium inserts to reinforce high stress locations and use the strongest glass in the smartphone industry," the spokesperson said.
Apple went on to say that workers did "rigorous tests throughout the entire development cycle including 3-point bending; pressure-point cycling; sit, torsion, and user studies. iPhone 6 and iPhone 6 Plus meet or exceed all of our high quality standards to endure everyday, real-life use."
The sit test "simulates users sitting on a hard surface in the highest stress position of having the iPhone in their backpocket of tight jeans. A single phone will endure thousands of cycles with the phone in multiple orientations," an attempt to inflict several years' worth of stress.
The spokesperson also said hundreds of Apple employees "lived on the phones, carrying the devices in various manners" before Apple began selling them, and Apple checked the performance of those phones over time.
The explanation comes on the heels of a highly viewed online video that showed a reviewer bending his phone. The reviewer said he decided to try to bend the iPhone 6 Plus after a family reported accidentally bending one. Other users online have claimed their phones bent somewhat after they sat with them in tight pants for hours at a time.
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CNBC asked whether Apple's tests subjected the phones to sustained warmth and bending pressure over several hours, simulating the experience of some online commenters who said their phones bent after sitting with them over a long period of time. CNBC has not yet heard back from Apple with an answer to that question.
CNBC did receive loaner iPhone 6 and 6 Plus devices to show on air and test during the launch period. The 6 Plus was bent using as much force as it took to bend a 162-page hardcover book, and it didn't budge.
Apple's defense is unlikely to quell criticism, however, until an independent third-party performs its own tests. Consumer Reports, the subscription-based publication that tests consumer products, has vowed to test the new iPhones and competing smartphones for bendability, and to release the results as soon as they're available.