If you’re an avid reader of tech news, you likely often have a good idea of what Apple is going to announce at any given product event. For a Google event, there’s a good chance that you’ve even seen videos of someone using a leaked product weeks in advance.

But when it comes to Amazon events, it’s not unusual to go in with very little idea of what’s to come. That’s true once again for today’s event: we know Amazon will announce new hardware, but we have little idea about the specifics of what’s in store.

There are a few reasons why Amazon is able to keep its announcements so well under wraps, some of which are unique to Amazon. The nature of the company means it’s very likely a lot better at securing its supply chain than most competitors, and because Amazon hardware isn’t as highly anticipated as products from, say, Apple, there may just be less demand luring it out into the world.

This isn’t a difference in marketing strategy. By and large, companies would prefer to keep their products under wraps so that they can get an edge on competitors that are eager to copy and compete with their products. Amazon is just one of the only companies regularly capable of actually keeping a secret.

Companies use a slew of tricks to keep announcements under wraps. In 2016, it came out that Apple would hide trademark applications by filing them first in countries like Trinidad and Tobago where you had to jump through hoops to request information on existing filings, like physically walking into an office. Amazon pulls a similar trick, using shell companies to prevent trademark applications from being linked back.

But a great deal of leaks come from outside companies, like retailers or, more often, the suppliers who are actually building these devices. External companies can be a lot harder to lock down, and that can lead to individual parts, schematics, or entire devices making their way out into the world weeks or months before they’re supposed to.

This is likely why Google has had such a hard time keeping the Pixel a secret. Google is relatively new to hardware and hasn’t had as much time to develop thorough procedures to keep its products from leaking. Amazon, on the other hand, has been making the Kindle for over a decade, and its entire business is based on properly moving items from one location to another. So it’s not a huge surprise that Amazon is better at preventing products from going missing, as seems to happen with Google every year.

Keeping a supply chain secure involves taking a number of seemingly simple steps that, if missed, can lead to huge problems. The issue can be as basic as security camera placement and monitoring, says Jim Yarbrough, a supply chain security leader at the standards body BSI. Even if cameras are placed correctly, companies can be exposed to security gaps if too many employees are then able to see exactly what those cameras are watching.

“We’ve seen that literally happen. That’s a gap right there, you shouldn’t be able to walk by and see what those monitors are showing,” Yarbrough says.

There’s also the matter of interest. Hundreds of millions of iPhones are sold every year, so there’s a reason for journalists, analysts, and fans to seek out information about what’s coming next. Entire businesses thrive around the iPhone, too. Accessories companies and case makers need to know what’s coming up so that they can prepare products and have them ready to ship on day one, lest some other company beat them to those sales. Also, because the iPhone is so key to Apple’s business, details about an upcoming model can move financial markets, making that information particularly valuable.

Hardware is a good business for Amazon — it sold “tens of millions” of Echos in 2018 — but it’s not as hugely important to the company’s bottom line. Paired with the fact that not as many people are going to buy an Echo each year (and speaker specs just aren’t as easy to get excited about as new phone features), there’s less incentive for those in the know to leak and for fans to hunt for leaks. Accessories for Amazon devices is also a much smaller market. Echo speakers largely stay at home on a table, so they don’t need cases, battery packs, extra cables, and so on.

What leaks we do get from Amazon seem to come from company insiders. CNBC had a report yesterday about upcoming Alexa-integrated earbuds that cited “a person directly involved in the project.” It also reported on a new Echo with higher sound quality.

So Amazon isn’t impervious to leaks, but it does seem to have a tighter lock on the areas where some of the largest gaps exist, preventing full reveals of devices months in advance.

That means our knowledge of today’s event is a lot more limited than our advanced knowledge of the typical tech event. We know the broad strokes, but that’s mostly due to history and what Amazon has teased. Even the specifics, like the Alexa earbuds, aren’t that specific. Will the earbuds be for casual listening like the AirPods, designed for sports use like the Powerbeats Pro, or something else? We don’t know.

Other companies would love to be in this position. It’d be a lot harder for competitors to copy Apple’s next advancement if they had to wait until those features were formally unveiled onstage. Amazon’s the only one that’s regularly been able to pull that off. But as hardware becomes more important to its business and Amazon devices make it into more people’s homes, keeping those secrets locked down could grow harder and harder.