The iPhone 6S and 6S Plus, introduced in 2015, feature 3D Touch displays which allow the screen to recognize how hard it is being pressed using pressure-sensitive multi-touch technology, and a new Taptic Engine to provide haptic feedback. In addition to visual cues, 3D Touch uses the Taptic Engine to provide a tactile sensation relative to the force being applied to the display to indicate to the user that a light or deep press action has been completed. An example of how this technology was used is lightly pressing the screen to preview a photograph and deeply pressing to open it, a feature dubbed 'Peek and Pop' by Apple.