iWatch revealed as Apple Watch, launching in multiple sizes

Apple has finally made the Apple Watch official. The long-rumoured wearable, originally expected to be called the iWatch, was revealed on stage during the company's iPhone 6launch event in Cupertino, signalling Apple's move into wearable technology for the first time.

It might not have a circular display like Motorola's eye-catching Moto 360, but the Apple Watch is still a beautiful looking wearable; depending on the model, the square chassis is either built from stainless steel or 18 karat gold, with curved edges and interchangeable wrist straps.

The screen uses a flexible retina display, laminated to sapphire glass to protect it from scratches and scrapes. It can sense force for the first time in an Apple device, detecting the difference between a tap and a press, but Apple says controlling a wearable by touchscreen alone isn't exactly ideal as you're covering the tiny display. Little is known about screen resolution yet, as Apple hasn't made anything official.

The Apple Watch gets around this with the Digital Crown, which turns rotary movements into digital actions onscreen. Turning the crown when looking at maps will zoom in and out, but when you're reading a list you'll scroll up and down instead. It also doubles as a home button, sending you back to the home screen with a press.

On the underside, four IR and LED sensors protected by more sapphire glass can detect the wearer's pulse, then feed the data back into the Health app on iOS 8. You can also share your heartbeat with other iWatch owners, although we aren't yet convinced many people will find a use for this niche feature. The button below Crown, which shows friends to contact, seems much more useful.

The back of the watch is made from tough zirconia, but doubles as a charging plate. With a combination of inductive charging and magsafe magnetic locking, there's no need to align charging pins or carry a bulky charging cradle with you. Apple hasn't yet revealed battery life, and with no firm details on battery capacity it remains the Watch's biggest mystery. The company was rumoured to be unhappy with battery life in prototype Watch models, but we're hoping Apple manages to squeeze at least two days from a single charge.

The Watch is powered by a custom-built Apple S1 system-on-chip, paired with what Apple is calling a Taptic engine - essentially a vibrating motor that provides physical feedback on receiving notifications.

The brand new UI doesn't look anything like iOS, with a series of circular icons letting you jump into any app from the one screen. The Apple Watch has Siri onboard for voice control and dictating messages, notifications for all supported apps and maps for walking navigation. According to Apple, it can also be used to control an Apple TV, act as a remote viewfinder for a paired iPhone camera, or pay for goods at participating stores with Apple Pay support. It will also support the iOS 8 Handoff feature, meaning you can dismiss a notification on your wrist and have it vanish from your other devices.

Two health and wellness apps, Fitness and Workout, will track your daily movement and measure your performance when out on a run or cycling, using a paired iPhone to track GPS location.

It will also be possible to completely customise the watch face with different colours, designs and features. Apple will include a range of its own watch faces, but expects third party developers to add many more. It will be launching the WatchKit SDK soon to see what they can come up with.

The Apple Watch will be launching in two different sizes, with a smaller watch that should be a better fit for smaller wrists, as well as three distinct versions. The standard Apple Watch will arrive in stainless steel, the Sport Collection will use a 60% tougher metal alloy, and the Apple Watch Edition will arrive in 18 karat gold.

You'll get different glass to protect the watch face display depending on the model you choose. The standard Apple Watch and Gold Apple Watch Edition both use sapphire crystal glass, which should be able to withstand serious scrapes and scratches, while the the Apple Watch Sport uses Ion-X Glass instead. Because sapphire glass isn't particularly resistant to drops, ion-strengthened glass makes more sense in a watch that will be worn during vigorous exercise.

Apple has designed six different straps, along with a mechanism for making it easy to swap between them. The Sport band is made from sweat resistant plastic, but you'll be able to choose between a leather quilted loop, stainless steel link bracelet and milanese loop.

You'll need to have an iPhone in order to use the Apple Watch, as it won't pair with anAndroid device, but it will work with the existing iPhone 5s, iPhone 5c and iPhone 5 as well as the newly announced iPhone 6 and iPhone 6 plus.

Customers will be able to get their hands on an Apple Watch early next year, with prices set to start from $349 for the standard model in the US. We'll just have to wait for a UK release date.