Reported details ahead of iWatch reveal: Two sizes, NFC pairing, pre-orders for 2015 launch

Five days out from what’s shaping up to be the most exciting Apple event in years, and what we still don’t know about Apple’s expected wearable wristband far outweighs what we do know.

But a few tidbits are leaking out: According to a new report in the Wall Street Journal, Apple’s iWatch will have built-in near-field communication technology. The wireless technology will be central to a new tap-to-pay service that Apple is expected to launch alongside the new iPhone and iWatch.

The new iPhone is also expected to have NFC included, the authors noted. As my colleague Kevin Tofel wrote last week, one overlooked use of NFC is the ability to tap-to-pair, which could be extremely helpful for easily connecting the iWatch to the iPhone.

The Wall Street Journal goes on to predict that Apple will launch its wearable wristband in two different sizes, both with curved OLED screens. As has been rumored for months, the device will include several different sensors for tracking biometric data for Healthkit. Although the iWatch is not expected to ship until 2015 as mass production does not seem to have started, Apple is reportedly planning to take pre-orders.

The details from the Wall Street Journal match up with a comprehensive article posted later on Thursday by the New York Times. That report, by Brian X. Chen, corroborates the iWatch release window, the inclusion of NFC, as well as Apple’s plans to announce two different sizes. It also adds a few new details: The iWatch is expected to have a “flexible display” with a sapphire crystal covering, and the device is expected to “rely on” wireless charging.

Chen adds that the larger iPhones expected to launch alongside the iWatch will come with a new “one-handed mode” to help ameliorate the ergonomics issues raised by a larger screen.

Most of these details can also be found in a new research note posted today by reliable Apple rumormonger and KGI Securities analyst Ming-Chi Kuo, via 9to5Mac.

Kuo also thinks Apple’s wearable wristband will come in two sizes, one with a 1.3-inch screen and one with a 1.5-inch screen, presumably to appear to both men and women, who may have varying size preferences. Both those screen sizes would be smaller physically than the 1.63-inch screens currently on Android Wear watches such as the ZenWatch.

Kuo corroborated the reports that the backside of the device will have various sensors for collecting health data and even teases some potential specs: 512MB of RAM, which matches most Android Wear devices, and 8GB of internal storage, which doubles the quantity in most smartwatches available today.

Part of the reason the iWatch has garnered so much buzz is the expectation that Apple is going to include creative new features that take the smartwatch beyond the notifications-based approach most of them have been mired in for the past year. With the increasing chatter surrounding Apple’s payment plans as well as its ambitions in health technology, it’s pretty clear that those two features will be included in Apple’s wrist-mounted wearable. But is Apple planning other major uses for its first foray into a new product category since the iPad in 2010?

Any further surprises should be revealed as part of Apple’s big event on September 9. Gigaom will be covering Apple’s announcement live from Cupertino.

This article was updated at 3:30 EDT to include additional information from the New York Times article.