group of smartphone models produced by Apple Inc.

The iPhone 4S looks like the iPhone 4 , but there are a lot of differences under the hood. Hardware includes Apple’s dual-core A5 processor, superior graphics, and support for both GSM and CDMA networks. And to top it off, there’s Siri.

The iPhone 4S also has better cameras: 8 MP on the back and 0.9 MP on the front, up from 5 MP and 0.3 MP respectively. This was the first iPhone to support 1080p video recording and the first with Bluetooth 4.0 support.

Apple took orders for over 1 million units in its first 24 hours of pre-orders and sold 4 million during the first four days of retail sales.

Specs (via Low End Mac)

• Announced: 2011.10.04, available 2011.10.14 at $199 (16 GB), $299 (32 GB), and $399 (64 GB) with a two-year wireless contract, $649, $749, and $849 respectively without contract. 16 GB model dropped to $99 in September 2012 with introduction of iPhone 5. 8 GB model introduced September 2013 and as the new “free with contract” model (otherwise $450).
• Cpu: 1 GHz dual-core Apple A5 clocked at 800 MHz
• Ram: 512 MB
• Video: up to 10 hours
• Display: 3.5″ 640 x 960 pixel 24-bit multitouch screen @ 326 ppi
• Code Names: N94
• Weight: 4.9 oz. (140 g)
• Dimensions: 4.5″ x 2.31″ x 0.37″ (115.2 x 58.6 x 9.3 mm)
• Included Accessories: earbuds, USB 2.0 30-pin dock cable
• Identifier: iPhone4,1
• Model Number: A1387 (worldwide), A1431 (China only)
• Architecture: 32-bit
• Graphics Engine: PowerVR SGX543
• Cameras Rear: 8.0 MP autofocus with LED flash, 1080p video front: 0.9 MP FaceTime camera
• Rear: 8.0 MP autofocus with LED flash, 1080p video
• Front: 0.9 MP FaceTime camera
• Sensors: proximity, ambient light, 3-axis gyroscope, accelerometer, assisted GPS, compass, Nike+iPod
• I/O Port: 30-pin dock connector
• Wifi: 802.11b/g/n (2.4 GHz only)
• Bluetooth: 4.0
• Networks: UMTS/HSDPA (850, 900, 1900, 2100 MHz) GSM/EDGE (850, 900, 1800, 1900 MHz) CDMA EV-DO Rev. A (800, 1900 MHz)
• Data: up to 14.4 Mbps via HSPA+
• Gps: Infineon PMB2525 assisted by EDGE, 3G, and WiFi
• Battery: 1430 mAh lithium ion
• Charge Time: about 4 hours (2 hour fast charge to 80% capacity)
• Battery Life: Talk: up to 6 hours on 3G, 14 hours on 2G Standby: up to 200 hours Internet: up to 6 hours on 3G, 9 hours on WiFi Video: up to 10 hours Audio: up to 40 hours
• Talk: up to 6 hours on 3G, 14 hours on 2G
• Standby: up to 200 hours
• Internet: up to 6 hours on 3G, 9 hours on WiFi
• Audio: up to 40 hours
• Original Os: iOS 5
• Maximum Os: iOS 9
• Itunes Versions: iTunes 10.5 and later.
• Mac Os Required: OS X 10.5.8 or later
• Windows Versions Supported: 7, Vista, XP Home or Professional SP 3 or later