Apple Watch apps
Apple Watch doesn't just beams all iPhone notifications to your wrist, it lets you play with and control all sorts of native Apple Watch apps with its touchscreen and digital crown.
Among Apple's 20 built-in apps are Messages, Activity, Workout, Calendar, Weather, Mail, Photos, Camera Remote, Music, Passbook and Apple Maps for navigation.
There were also 1,000 of third-party Watch apps submitted to the App Store even before Apple Watch's launch. It's all thanks to entruperal developers taking advantage of Apple's WatchKit software.
Apple Watch heart rate monitor
Apple Watch's two built-in fitness apps make use of its heart rate monitor and other sensors. Its Activity app tracks movement, exercise minutes and how long the wearer stands.
The smartwatch can also - optionally - ping you when you're unhealthily sitting idle for far too long, like the Jawbone Up24 can do. If "sitting is the new cancer," as Tim Cook said, this is a potential solution.
Apple Watch's other app is Workout, which gives real-time stats for your total exercise time, distance, calories and pace. Keeping you motivated are goals, reminders and achievements.
But it could become world's best running watch one day with the right training. The company has been fine tuning its custom heart rate monitor and other sensors in a secret gym lab over the last two years.
- Which is better at fitness? Apple Watch vs Microsoft Band
Apple Watch battery life
The Apple Watch battery life is supposed to last all day, but don't expect a full 24 hours from this first iteration of the smartwatch.
Instead, Tim Cook has promised 18 hours of a typical day, which technically does sync with his comments that it can be "worn all day" and is something that's "simple to charge at night."
This number is based on an Apple Watch being paired with an iPhone and used for 90 time checks, 90 notifications, 45 minutes of app use and a 30-minute workout with music playback via Bluetooth.
The Apple Watch battery size is 205mAh for the 38mm case, which is half that of other top Android Wear watches, and the 42mm case features a slightly bigger lithium-ion battery.
Luckily, there's a Power Reserve mode that kicks in when the battery life is critical, giving users an extra 72 hours of juice. Either sizes' watch battery, said to stay good for 3 years, can be replaced - by Apple.
We have to test out the Apple Watch to see how it stacks up. At least the disturbing reports about it having as little as 2.5 hours of battery life were unfounded. As we predict, these fears were overblown and likely based on an always-on screen or an Apple Watch prototype.
Apple Watch magnetic charger
There's no USB port on the Apple Watch. Instead, its crystal back houses a magnetic inductive wireless charging solution similar to the MagSafe design.
Again, Apple bucks another trend here - this time it's eschewing the popular Qi wireless charging method - in favor of its own inductive charging standard.
As pointed out at the end of our Apple Watch price range guide, an extra magnetic charger can be bought as an accessory. The 1m cable length is $29 (£25, AU$45) and a longer 2m cable is $39 (£29, AU$59).