The iPhone 4S was the product that first introduced the Siri voice assistant. The iPhone 4S was designed around a stainless-steel body with a glass front and back. It had a 3.5-inch LED-backlit 960×640 326 ppi multi-touch Retina display and included two noise-cancelling microphones. It was available in black or white.
The iPhone 4S supported both GSM and CDMA networks and included 802.11b/g/n and Bluetooth 4.0. It used a dual-core Apple A5 processor; 512 MB of RAM; and 8 GB, 16 GB, 32 GB, or 64 GB of internal storage. It had two cameras: an 8 megapixel HD camera (1080p at 30 FPS) with an LED flash on the rear and FaceTime camera on the front that allowed FaceTime video calls over Wi-Fi.
Source: EveryMac.com