The iPhone XS and iPhone XS Max are smartphones designed, developed, and marketed by Apple. Released as the twelfth-generation flagship models of the iPhone, they succeeded the iPhone X and were unveiled alongside the lower-end iPhone XR on September 12, 2018, during a keynote address by Apple CEO Tim Cook at the Steve Jobs Theater at Apple Park in Cupertino, California. Pre-orders began on September 14, 2018, with general availability starting September 21, 2018. The iPhone XS and XS Max introduced improvements over their predecessor, including enhanced processing power, dual-SIM functionality, improved water resistance, and stereo audio recording for video capture.