screen, up from the 3.5-inch screen of all previous iPhone models, as well as faster 4G LTE connectivity. It also introduced a thinner and lighter body made of aluminum alloy, and the 30-pin dock connector of previous iPhones was replaced with the new, reversible Lightning connector. The iPhone 5S and iPhone 5C were announced on September 10, 2013. The iPhone 5S included a 64-bit A7 processor, becoming the first ever 64-bit smartphone; it also introduced the Touch ID fingerprint authentication sensor. The iPhone 5C was a lower-cost device that incorporated hardware from the iPhone 5, into a series of colorful plastic frames. On September 9, 2014, Apple introduced the iPhone 6 and iPhone 6 Plus, and included significantly larger screens than the iPhone 5S, at 4.7-inch and 5.5-inch respectively; both models also introduced mobile payment technology via Apple Pay. Optical image stabilization was introduced to the 6 Plus' camera. The Apple Watch was also introduced on the same day, and is a smartwatch that operates in conjunction with a connected iPhone. Some users experienced bending issues from normal use with the iPhone 6 and 6 Plus, particularly on the latter model, and this issue was nicknamed "bendgate". The iPhone 6S and 6S Plus were introduced on September 9, 2015, and included a more bend-resistant frame made of a stronger aluminum alloy, as well as a higher resolution 12-megapixel main camera capable of 4K video recording. The first-generation iPhone SE was introduced on March 21, 2016, and was a low-cost device that incorporated newer hardware from the iPhone 6S, in the frame of the older iPhone 5S. The iPhone 7 and 7 Plus were announced on September 7, 2016, which introduced larger camera sensors, IP67-certified water and dust resistance, and a quad-core A10 Fusion processor utilizing big.LITTLE technology; the 3.5mm headphone jack was removed, and was followed by the introduction of the AirPods wireless earbuds. Optical image stabilization was added to the 7's camera. A second telephoto camera lens was added on the 7 Plus, enabling two-times optical zoom, and "Portrait" photography mode which simulates bokeh in photos. The iPhone 8, 8 Plus, and iPhone X were announced on September 12, 2017, in Apple's first event held at the Steve Jobs Theater in Apple Park. All models featured rear glass panel designs akin to the iPhone 4, wireless charging, and a hexa-core A11 Bionic chip with "Neural Engine" AI accelerator hardware.