Although the iPhone 4S looks like the iPhone 4 before it, it is considerably more powerful and most notably unveils a new voice-controlled "intelligent assistant" named Siri.
The iPhone 4S uses a stainless steel body design with an ultra high-density 3.5-inch, IPS, LED-backlit 960x640 326 ppi multi-touch "retina" display, dual noise-cancelling microphones, mobile and data antennas integrated in the "metal band" that wraps around the sides of the phone, and a chemically hardened "aluminosilcate" glass front over both the display and a black or white frame and the chemically hardened black glass back, too. Both the front and back have an "oleophobic" oil repellent coating, as well.
The iPhone 4S also has dual cameras -- an 8 megapixel HD video/still camera (1080p at 30 FPS) with a "backside illuminated sensor," and an LED flash on the rear and a VGA quality video/still camera on the front designed for video conferencing over a Wi-Fi network with Apple's included "FaceTime" application.
It is powered by a dual-core "Apple A5" processor, has 512 MB of RAM, and has 8 GB, 16 GB, 32 GB, or 64 GB of internal storage.