After almost four years in the making, Tesla will finally reveal the Model Y compact SUV tonight at an event in Los Angeles. While we still haven’t seen a full picture of the new electric car, Tesla and CEO Elon Musk have spent the last few years, months, and days leading up to the unveiling sketching out a decent outline of what to expect.

Broadly speaking, the Model Y will be a crucial car for Tesla that presents the company with a huge opportunity. Simply put, SUVs are selling like hotcakes these days. They currently account for about 49 percent of the new car market in the United States, according to JD Power, and more than half of customers who bought a vehicle last year in the $30,000 to $50,000 price range purchased an SUV.

SUVs are selling like hotcakes

In other words, you could build an SUV out of Lego and sell it for five figures in the US right now. So if all goes well, demand for a car like the Model Y should be strong.

We don’t know exactly what is in store for tonight (and both Tesla and Musk seem to love surprises), but here are our best guesses.

The specs

The Model Y will share about 75 percent of the parts that make up the Model 3, so we can expect it to offer similar performance, style, and overall cost. We don’t have exact specifics on the Model Y yet, but Musk offered ballpark estimates on Twitter just 11 days ago. He said the Model Y will be about 10 percent bigger than a Model 3, cost about 10 percent more, and have “slightly less range for [the] same battery.”

That means the Model Y should eventually start at about $38,500, and run as high as about $63,800 (before options like Autopilot). Of course, it’s likely that Tesla will start by making and selling the most expensive versions of the Model Y when it goes into production in 2020 since those will have the highest margins. One thing to look for tonight is whether Musk offers a timeline for the base version of the Model Y.

If the Model Y has “slightly less range” with the same battery, that means the base version (which will likely be referred to as the “standard range Model Y”) will offer a little less than 220 miles on a full charge. The most expensive Model Ys will be capable of traveling about 300 miles.

The design

Try to edit the newest shadowy teaser image that Tesla released for the Model Y in order to get a glimpse of what it looks like. I dare you. All you’ll really end up with is a slightly more washed-out image with a hidden message: “Nice try.”

That said, the difference between the new teaser image and the one that Tesla distributed a few years ago is significant. The new image really shows off the shape of the Model Y in a way that the old image didn’t. It’s never easy to get a sense of what a car will look like until you see it in full (which, duh), but Tesla’s newest teaser does give the impression that the Model Y will resemble a taller, more sharply angled Model 3. What it certainly won’t be is a car that is as big or bulky as the Model X.

The long road to get here

Musk first teased the Model Y in an October 2015 tweet, which he almost immediately deleted. Since then, the crossover SUV project has endured a number of shifts in scope. While it was originally thought that Tesla would build the Model Y on the same technological base as the Model 3, Musk said in May 2017 that Tesla instead wanted to build the Model Y on a “completely different” platform. He said at the time that the company could simplify the production process and dramatically reduce the length of electric wiring needed if it ditched the 12-volt battery architecture used in Tesla’s other vehicles. It would also have the Model X’s Falcon Wing doors.

But this was all said at a time when Musk was still fully gung-ho on automating a major amount of the production process. That has changed. Musk now says Tesla relied too heavily on automation, which was one of the reasons it took the company longer than it planned to get Model 3 production running at a steady pace. Musk eventually did an about-face on the Model Y, telling investors in August 2017 that it would share a platform with the Model 3 after all.

At one point, the Model Y wasn’t going to share anything with the Model 3

“Upon the counsel of my executive team, to reel me back from the cliffs of insanity, the Model Y will, in fact, be using substantial carry over from Model 3 in order to bring it to market faster,” Musk said on that call. That’s remained the plan ever since, though Musk did admit this month that the Model Y now won’t have the Model X’s Falcon Wing doors.

Knowing the car has been in development for that long, something to watch for during the event is whether Tesla has come up with other ways to distinguish the Model Y from the Model 3. Will the interior be exactly the same? Or will Tesla mix things up by adding a few more physical buttons, a heads-up display, or something totally different? One thing’s for sure: expect a big touchscreen to dominate the Model Y’s dashboard.

What we don’t know

Where to begin? For one thing, Tesla and Musk haven’t fully committed to where the Model Y will be built. The company’s Fremont, California, manufacturing plant is so packed that Tesla had to erect a tent in order to build the Model 3 at scale there last year. Musk said it’s “likely” the Model Y will be built at the company’s Gigafactory in Reno, Nevada, and versions of the car due for China will also probably be made at the factory currently being constructed in Shanghai.

It’s possible that the Model Y will have a third row of seats, though it’s not a lock since that rumor was based on internal documents that a Tesla spokesperson called “outdated.”

While Musk has said the Model Y will start production in 2020, it’s not fully clear what the company’s timeline is for the new car. Tesla and Musk are notorious for missing deadlines, but any concrete dates announced tonight would help fans, followers, and Wall Street calibrate expectations for the Model Y over the coming months.