Apple announced a new smartwatch at the beginning of September in the form of the Apple Watch Series 2. This comes in a standard model, a Nike+ model, Hermès model and an Edition model.

The new device sits alongside the Apple Watch Series 1, which is essentially the same as the original device that hit shelves in April 2015, but with a new dual-core processor.

It's all a bit confusing so to make matters a little more simple, we've compared the Apple Watch Series 2 to the Apple Watch Series 1 and the original Apple Watch (2015) so you can see exactly what the differences and similarities are.

The original Apple Watch features a rectangular solid body that sees the crown and separate button on the right, with a speaker and microphone on the left. The heart rate monitor sits on the underside of the body, along with the release buttons for switching out the straps and the OLED Retina display sits on top.

The Apple Watch Series 1, which replaces the original model, is exactly the same as the original in terms of design. Nothing has changed. It is still splash resistant, it still features Ion-X glass on top of the display and it still offers the same functionality.

The Apple Watch Series 2 also offers the same design, meaning all those straps you may or may not have bought, will still be compatible. There are a couple of differences compared to the Series 1 and original though. For starters, Apple has waterproofed all the entry ports meaning the Series 2 is not just splash proof, but swim-proof up to 50-meters, and the body is also ever-so-slightly thicker for a bigger battery.

The new device also has a second-generation OLED Retina display that is two times brighter than the Series 1 and original at 1000nits, compared to 450nits. The Series 2 uses Ion-X glass to protect the screen on the aluminium case models, like the Series 1, but sapphire glass is present for the stainless steel and ceramic models.

When the original Apple Watch launched, its case was available in aluminium, stainless steel and special materials including solid gold, all of which came in two size options of 38mm and 42mm.

As we mentioned, the original has now been discontinued with the Series 1 taking its place, but although the size options remain, this model only comes in the aluminium case option with a Sport Band. You can of course buy separate straps, but you won't be able to get the Series 1 in stainless steel or any other special material.

The Series 2 comes in the same size options again, and in a standard model, the Nike+ model, the Hermès model and the Watch Edition model, as we mentioned at the start. The standard model comprises the aluminium case with a Sport Band or Nylon Woven band, or the stainless steel case with Sport Band, stainless steel band or leather band.

The Nike+ model is an aluminium case with Nike Sport Band, while the Hermès model is a stainless steel case with Hermès branding and it comes with a Hermès band and Sport Band included.

The Watch Edition model is a ceramic case with Sport Band. The solid gold Apple Watch is no more on any model.

The Apple Watch Series 1 and original Apple Watch are identical in terms of hardware, except the processor. The Series 1 has an upgraded dual-core processor called the S1P, while the original model has the S1 processor.

Both models feature Bluetooth 4.0, 2.4Ghz Wi-Fi 802.11/b/g/n, a heart rate sensor as we mentioned, accelerometer and a gyroscope. They also both have an ambient light sensor and they are splash resistant but not waterproof, as we mentioned. A built-in lithium-ion battery is under the hood of both with a life of up to 18 hours.

The Apple Watch Series 2 offers the same hardware as the Series 1 when it comes to Bluetooth, Wi-Fi and the various sensors. The battery is said to be larger by roughly 30 per cent though.

It also adds a different dual-core processor called the S2. This chip allows for built-in GPS, which combined with the waterproofing and the brighter display make for some significant differences between Series 2 and Series 1.

The Apple Watch Series 2 launches on WatchOS 3, which the Series 1 and the original device saw an update to from 13 September.

There have been several new features added to the new software including enhancements to messages, a new app called Breathe that wants to help you better manage everyday stress and a new Workout app.

The Series 2, Series 1 and original Apple Watch will all therefore offer almost identical user experience but thanks to the added hardware features of the Series 2, the newer device will have a few extras here and there.

The waterproofing means the Series 2 will be able to track swimming and Apple has added features like automatic stroke recognition for an accurate calories burned measurement, while built-in GPS means outdoor hikes, runs and bike rides can be mapped precisely without the need to bring your iPhone along.

The original Apple Watch is no longer available to buy, but the Apple Watch Series 1 starts at £269.

The Apple Watch Series 2 starts at £369, as does the Apple Watch Nike+ model. The Hermès model starts at £1149 and the ceramic Watch Edition model starts at £1249.

The Apple Watch Series 1 and Series 2 are available to buy now.

The difference between the original Apple Watch and Series 1 is literally just the processor, meaning upgrading from the original to the Series 1 would probably not be worth it.

If you didn't invest in the original and you've decided the Apple Watch is now something you want, buying the Series 1 over the new model will save you £100, but you miss out on some key features.

The Apple Watch Series 2 not only adds a new processor, but it offers a much brighter display, built-in GPS, a bigger battery and that all important waterproofing. All the other features might remain the same, including design, but for some, the built-in GPS and waterproofing will be the two features they needed to take the smartwatch plunge.