The iPhone 6S and iPhone 6S Plus (stylized as iPhone 6s and iPhone 6s Plus) are smartphones designed by Apple Inc. The devices 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 and were the flagship devices of the iPhone series until September 7, 2016 when they were replaced by the iPhone 7 and iPhone 7 Plus.[15] The iPhone 6S has a similar design to the 6 but updated hardware, including a strengthened chassis and upgraded system-on-chip, a 12-megapixel camera, improved fingerprint reader, and LTE Advanced support. The iPhone 6S also introduces a new hardware feature known as "3D Touch", which enables pressure-sensitive touch inputs. The iPhone 6S and 6S Plus set a new first-weekend sales record, selling 13 million models, up from 10 million for the iPhone 6 and 6 Plus in the previous year.[16]