Amidst other hardware leaks and an ever-turning rumor mill, Sony has kept mum thus far about what it will show on stage from 3-5 p.m. ET. Instead, we're left with some strong, well-founded suspicions about what to expect from the PlayStation Meeting.
The high-end PlayStation 4 "Neo"

Sony confirmed in June that it would bring a high-end PS4 model to market, one that’s 4K-capable. Known just as "Neo" for now, we expect for it to get a name, price tag and first look tomorrow. Expect it to have similar specs to the upcoming Xbox One "Project Scorpio," which Microsoft debuted at E3 2016. Sony held off on making its own announcement at that event, likely to devote much of tomorrow’s showtime to it instead. The speculation now seems to be around the console’s release date, with some pointing toward sooner than later. Rest assured that we’ll have many of our "Neo" questions answered tomorrow.
The actual reveal of the PlayStation 4 slim

The industry’s worst-kept secret right now is this hardware revision, a trimmed-down version of the current PlayStation 4. We’ve seen it boxed and unboxed. We’ve seen it from every angle. We’ve seen its insides. (You can even take a look yourself below.) Everyone knows it exists, but Sony hasn’t admitted that the slim PS4 is on its way. Nothing is guaranteed at tomorrow's PlayStation Meeting — except for the official reveal of this console, along with its launch date and price. We’re sure of it.

PS4 slim

A tweak on the old DualShock 4

Along with the slim, we’ve seen a revised DualShock 4 controller in early hands-on looks at Sony’s new hardware. It’s not much different than the current DualShock 4 you own, but the changes are obvious: The face buttons have gone gray, and the light indicator shines through the touchpad now instead of just the top of the controller. We should get a better look at the controller tomorrow.
One more look at PlayStation VR

Sony's virtual reality headset is almost here, and tomorrow's event is one of the last chances Sony has to drum up interest before launch. PlayStation VR hits retail on Oct. 13, and considering it costs about as much as the required PS4 does, it would be wise for Sony to spend stage time getting fans pumped for it. We'd be shocked if a portion of the event doesn't entail people driving fast cars or shooting at some creepy monsters while wearing that fancy piece of hardware on their faces.

PlayStation VR

What’s going on with PlayStation Vita?

Okay, maybe don’t expect this to be addressed. But Sony’s handheld has been on its last legs since, well, shortly after launch. Will the company cement its fate tomorrow, either by properly killing it off or announcing a Vita revision of its own? The latter seems unlikely; Sony didn't mention its handheld at all at E3 2016, and if it doesn't here, we know it is dead in the water. With two hours of PlayStation time on the books, however, anything is possible.
Games — we hope

Much of the focus tomorrow will be around the hardware Sony wants to get in the hands of PS4 owners and newcomers alike. Yet the console has a healthy release calendar that we’d be happy to see more from tomorrow. Exclusive games like The Last Guardian, God of War, Spider-Man and Horizon Zero Dawn would make for nice featured guests at the event, but with Gamescom having just passed and Tokyo Game Show on its way, it’s anyone’s guess as to what games we’ll see. Maybe there are "Neo" exclusives on the way, although Sony previously said it will play most of the same titles as the current console.
Where can I watch this thing?

Sony is streaming live starting at 3 p.m. ET. We’ll have that feed available here on Polygon, and we’ll also be covering all of the breaking news live as it happens. Stay tuned, and keep your fingers crossed that everything you hope to see makes an appearance