Larger 4.7-inch and 5.5-inch display: The iPhone 6 has a Retina HD display , about two times the resolution of the iPhone 5 display. At 1,334 x 750 resolution (or 326 pixels-per-inch) for the iPhone 6, and 1,920 x 1080 resolution for the iPhone 6 Plus, the new smartphones have more than 2 million and 3 million pixels, respectively.

64-bit A8 chip: The two new smartphones contain the next-generation A8 chip, which has 2 billion transistors, double that of the first-generation A7 chip.

M8 co-processor: This new co-processor works alongside the main chip to continuously measure motion data without draining battery life. The M8 co-processor is designed for fitness and activities, it was announced. It can now figure out elevation, such as with a flight of stairs. It also comes with a new sensor called the Barometer, which measures elevation from air pressure.

Improved 8-megapixel camera: The camera is improved from the iPhone 5s, with a few new additions, like a new and improved sensor. The True Tone flash changes color depending on surrounding lighting, and images should come with greater noise reduction technology. The auto-focus is twice as fast as before, executives said. Panoramic photos now go up to 43 megapixels in size. The iPhone 6 Plus, however, comes with optical image stabilization. 

Near-field communications (NFC) for mobile payments: Apple's latest smartphones will come with a mobile payment feature, made possible with a near-range wireless chip that will allow users to pay for low-priced products from their device.

Better battery: At least, proportionally. Apple's Phil Schiller said the new devices will be as good as, if not better than, the iPhone 5s. Expect about 11 hours of video watching and Wi-Fi browsing, and about 14 hours of video and browsing on the iPhone 6 Plus.

Faster networking, LTE: Next-generation speeds are now up to 150 Mpbs, compared to 100 Mbps in previous models. The iPhone 6 and 6 Plus also come with 802.11ac networking for faster home and office speeds.

Apple Pay: A new mobile payment system, using the iPhone 6's new NFC chip, will allow users to pay for low-priced products from their device. Integrating with Touch ID and Passbook, users can add a new card from iTunes or by scanning their card with the camera.

HealthKit: Health, a dedicated app, and slated to work with third-party apps and services, it integrates with leading institutions so it can link with doctors and hospitals. It works seamlessly with Apple Watch, the company's new wearable.

Wi-Fi Calling: You can now (carrier supported) make calls over home or work Wi-Fi networks. It is supported on T-Mobile in the US, and EE in the UK for now.

Handoff: If you're working on your Mac and you need to switch between devices, you can "handoff" to your iPhone or iPad, running iOS 8, so long as you are within a close proximity. Many existing apps, like Safari, Mail, and Messages, will work from the start, as will many third-party apps offering support.

iCloud Drive: iPhones and iPads running the latest iOS 8 software will have its own dedicated app for browsing through your iCloud, similar to a cloud-based file manager.

QuickType and third-party keyboards: New predictive typing suggestions for words, allowing users to type out text messages and emails faster. By using context suggestions, different patterns and styles of writing are predicted based on who you are contacting. Additional and third-party keyboard support will also come with iOS 8, paving the entrance for major alternatives, such as SwiftKey.

Interactive notifications: Users can now pull down from a notification and reply there and then, without having to leave the app you're in.

Text messages support in iMessage: Traditional SMS messages will now synchronize across iMessage to other devices, including Macs.

Apple-designed leather cases will be available in black, soft pink, olive brown, midnight blue and (RED) for $45 (US) for iPhone 6 and $49 (US) for iPhone 6 Plus and silicone cases in black, blue, pink, green, white and (RED) for a suggested retail price of $35 (US) for iPhone 6 and $39 (US) for iPhone 6 Plus through the Apple Online Store  (www.apple.com), Apple’s retail stores and select Apple Authorized Resellers.

iPhone 5s will be available in the US for a suggested retail price of $99 (US) for the 16GB model and $149 (US) for the 32GB model, and an iPhone 5c 8GB model will be available for free.⁴ iOS 8 will be available as a free software update starting on Wednesday, September 17. Some features may not be available on all products. Apple Pay will be available to US customers as a free software update to iOS 8 this October.