On Sept 10, Apple will unveil two new smartphones in the iPhone 5S and iPhone 5C, leading to a supposed release date on Sept 20 that would allow buyers in the U.S. China and Japan to get the handsets ahead of other markets.

In the lead up to the grand debut, the 5S and the 5C became the subjects of intense discussions and rumours, providing for Apple fans specs and features that are seemingly real. While the flood of details are overwhelming, a careful look on what we have so far about the new iOS devices provides clear clues on their builds and capabilities.

And the list below of what experts believe as confirmed iPhone specifications should further crystallise what the 5S and 5C are in the minds of their future owners.

Significant specs boost

The 5S, according to earlier reports this year, is what the name suggests. The 'S' reflects what it stands before in the iPhone 3GS and the iPhone 4S - incremental jumps from previous versions.

However, analysts insist that the 5S is no minor work from Apple. The main cam shooter will be more powerful, boasting of 12MP lens, image stabilisation, low-light shooting optimisation and a host of camera applications to please both camera enthusiasts and professionals.

Powering the gadget is an A7X processing chip that reportedly is equipped with 64-bit computing, which should be a sufficient power-plant for a 4-inch screen that is flooded with some 1.5M pixels, thanks to the new breed of Retina display panel.

And the 5C is no pushover at all despite its mid-range specs listings. While wrapped in plastic casing to push down the retail price, the mobile phone is set to deliver major improvements from what users have seen in the iPhone 4 and 4S.

More fashionable iPhones

It could be that the iPhone 5S is a virtual iPhone 5 clone in the looks department but a major tweak is in the offing. Besides the conventional black and white housing, it is believed that Apple will retail its 2013 flagship in champagne gold and graphite, bringing four irresistible colour options for buyers.

The same is true with the 5C, which reports said will be sitting on store shelves in white, green, pink, yellow, pink and orange. These bright hues to choose from should widen Apple's traditional customer base, luring consumers who give premium on handsets literally are functional eye-candies.

Fingerprint scanner

Since Apple acquired biometrics expert AuthenTec in 2012, whispers of upgraded security protocol in iPhones and iPads gathered more steam. Analysts insist that 2013 versions of the iOS devices will come with fingerprint sensors that identify, say an iPhone 5S owner, and block unauthorised access in the event the gadget is stolen.

The fingerprint scanner will be embedded underneath the revised 5S Home button and coated with sapphire to guard against natural wear and tear or excessive use. Unfortunately, the feature is 5S exclusive for the initial deployment.

More killer features thanks to iOS 7

Android rivals are going big but Apple is sticking to 4-inch. It is true that consumers are slowly training their attention on mobile phones that sport 5-inch screen and up but according to analysts, the iPhone 5S will still command long queues and record sales on D-Day.

The key is the host of killer features that are packed with the gadget, thanks mainly to the redesigned Apple mobile platform - the iOS 7. It has become less cluttered and more straightforward in delivering A1 smartphone and experience that is unique in the iPhone ecosystem.

Come their Sept 10 unboxing, the iPhone 5S and 5C release date will follow 10 days after, with Apple focusing first on select markets.