The iPhone 6S and iPhone 6S Plus (stylized as iPhone 6s and iPhone 6s Plus) are smartphones designed by Apple Inc. The devices are part of the iPhone series and were announced on September 9, 2015, at the Bill Graham Civic Auditorium in San Francisco by Apple Inc. CEO Tim Cook. The iPhone 6S and iPhone 6S Plus jointly serve as successors to the iPhone 6 and iPhone 6 Plus of 2014. The iPhone 6S and iPhone 6S Plus are the performance versions over their respective predecessors, featuring improved hardware specifications, including 3D Touch, a force-sensitive touchscreen; upgraded rear-facing and front-facing cameras; a faster processor; a new chassis made of a stronger 7000 series aluminium alloy; second-generation fingerprint recognition Touch ID; improved LTE and Wi-Fi connectivity; and a new rose gold finish in addition to the space gray, silver, and gold finishes found on the previous models, while maintaining an identical design. The devices ship with iOS 9 preinstalled. As of September 28, 2015, 13 million iPhone 6S and 6S Plus models have been sold, setting a new first-weekend sales record, up from the 10 million iPhone 6 and 6 Plus units sold the previous year.