It feels like there have been iWatch rumors going back basically forever, but the strange thing is that they really only kicked off about a year and a half ago. Stranger yet: we still don't have a perfectly clear picture of what Apple's built. Its latest phones and tablets have all leaked out pretty thoroughly before their announcements, but details on the so-called iWatch have been inconsistent and piecemeal at best.

We're now just days away from finding out what Apple's actually been working on. That hardly means that it's time to rest our curiosity, though — we're still as eager as ever to find out what the iWatch is like. Here's our breakdown of all the reports and rumors that we've seen over the past year or so as we try to figure out exactly what to expect from Apple on Tuesday.

It'll tell the time

It's probably safe to call it a smartwatch. Some recent reports with knowledge of the device have carefully referred to Apple's creation as merely a nondescript "wearable," but stories going back for well over a year have used the "smartwatch" moniker. Who knows what Apple's going to call it, but it's pretty safe to say that this thing sits on your wrist and tells the time.

It'll track your health

Health tracking should be the iWatch's big feature

The iWatch's standout feature is believed to be a fairly robust set of health-tracking sensors. It's not known exactly what it'll be able to track, however, and a lot of potential sensor options have been thrown out there. Currently on the list of potential things that it might track: heart-rate, blood sugar, blood pressure, air pressure, altitude, temperature, weather, ultraviolet light exposure, calories, steps, sleep. Some of those seem a lot more likely than others, but it's worth remembering that Apple appears to hope that this device will be able to serve some basic medical functions. It's even been seen meeting with the FDA to talk about health.

It'll be an extension of your iPhone

The iWatch is probably running iOS, but it won't be able to do everything your phone can on its own. Reports suggest that the iWatch will need to be paired with an iPhone in order to send text messages or place phone calls. That's potentially a good thing, though, as it means that you likely won't need to pay for a separate service plan for the watch. Presumably, the watch will display notifications, allow you to perform basic phone functions, and even have apps — but, surprisingly, there has been very little detail on any of that. We really don't know how much it'll be capable of.

It'll come in two sizes

Everyone has their own preference on watch size, and Apple's apparently ready to give buyers some amount of choice there. It's been reported that the two sizes options could be anywhere from as small as 1.3-inches (which would be a touch smaller than the average Android Wear smartwatch) to as large as 2.5-inches (which would be larger than even Samsung's Gear S). A number of reports have honed in on a 1.5-inch display option, though, and that sounds like a fairly reasonable bet. Whether that'll be the large model or the small model still isn't quite clear though.

It'll have multiple price options

You may not have to spend a fortune on one

Apple is said to be looking at pricing the iWatch at around $400, according to Recode. But other models of the watch may be more or less expensive than that. It's not clear how those will break down, but there are some natural guesses: the larger model and the models with more storage inside of them might just cost you more.

No one's positive what shape the iWatch is

The iWatch is a band that you put around your wrist. But whether it has a circular watch face, a square watch face, or a large rectangular display on top of it still doesn't seem to be something that's reliably been answered. Recent reports have pointed to it being rectangular or slightly-rectangular, though many early reports seemed to think that it would have a circular face. The difference between the two is a big one, and it would establish whether Apple is planning a modern spin on the classic watch, or whether it's trying to create a brand new form of wrist-wear.

It'll be able to do a lot wirelessly, including pay for things

With something this small, you can't be bothered with cords. It's expected that the iWatch will take advantage of wireless charging, and — naturally — it'll do its pairing with your iPhone wirelessly too.

The really big wireless feature, though, is NFC. NFC is a type of short-range, wireless communication that can let a device do a whole host of things. And, most importantly, it's able to communicate fairly securely because of how short its communication range is.

Apple is supposed to be unveiling a mobile payments service alongside the iWatch, and the watch will be able to hook into that thanks to NFC. Just by tapping the watch on a compatible receiver when you're checking out at a store, you'll be able to pay a bill using your credit card — all without taking out your wallet.

Its screen will have four interesting features on its own

Let's break this down:

1. It's going to be curved. It's not expected to have a significant curve, but it's believed that the iWatch has a slight arch to its display.

Curved, flexible, and well-protected

2. It's going to be covered in sapphire crystal. Apple just opened a big manufacturing plant in Arizona specifically for the purpose of manufacturing this. The screen won't look any different because of it, but it should be more scratch resistant than most glass — and that's pretty important for a screen hanging off your wrist.

3. It's going to be "flexible." It's not clear exactly how this will work given the sapphire crystal over top of it, but it's possible that the screen will have a slight flex to it for safety purposes. It's also possible that this is just an invisible facet of it being slightly curved. Who knows, though. Perhaps Apple has something more ambitious planned. LG is supposed to be supplying the displays, and it certainly has the technology.

4. It'll have some type of OLED technology. OLED's are often known for their over-saturated colors, but they have some important advantages. Namely, individual pixels can be turned on and off as needed. That means that a watch might be able to display some basic information (like the time or a notification) while leaving the rest of its display blank. If that's how Apple chooses to use it, it could mean big battery savings.

You won't be able to buy it until next year

There's at least one good reason that we don't know all that much about the iWatch just yet: Apple hasn't really kicked off production on them. Though Apple plans to unveil the watch on Tuesday, it isn't expected to be in stores until after the holidays. It sounds as though Apple may have liked to have its watch ready before then, but there may be a lot for it to do between now and when the watch goes on sale — perhaps even running it by regulators.

There are still some big questions remaining

There's a whole lot that we still don't know about the iWatch, but here are a few points that stick out to us: How waterproof will it be? Will it have any buttons? Will it let you control smarthome devices? Will it be designed like a fashion accessory or a tech accessory? Will it actually be called the iWatch? How long will its battery last for? (For several days, we're hoping.)

All told, that should make Apple's event on Tuesday a pretty interesting one. Unlike in previous years, we don't know every single detail of what to expect. This is a brand new device, and Apple has done a good job of keeping it under wraps. Now, let's just hope we're pleasantly surprised.