iPhone 6s have a 4.7" (diagonal) widescreen pressure-sensitive "3D Touch" LED-backlit 1334x750 native resolution (326 ppi) "Retina HD" display with "IPS technology and a taptic engine,", dual cameras -- a rear 12 megapixel, 4K "iSight" camera with 1.22 micron pixels, an f/2.2 aperture, and support for simultaneous 4K video and 8 megapixel still photography as well as a front 5 megapixel, 720p "FaceTime" camera.
The iPhone 6s is powered by a 64-bit 1.85 GHz "Apple A9" processor and has 2 GB of LPDDR3 RAM and 16 GB, 32 GB, 64 GB, or 128 GB of flash storage. It also supports 802.11a/b/g/n/ac Wi-Fi with MIMO, Bluetooth 4.2, LTE (4G), and NFC for Apple Pay. It has a bottom-mounted headphone jack and uses a "Lightning" port to connect to a Mac, PC, dock, or power adapter.