Apple (NASDAQ:AAPL) usually hosts several product events every year. And one of them is this month -- on Monday, March 21 to be exact. Here's what to expect, as well as how to tune in.

Likely announcements
iPhone SE: The most prevalent rumors ahead of Apple's event later this month are surrounding a new iPhone. But don't expect the iPhone 7. Speculation points to a new phone Apple has reportedly dubbed the "iPhone SE." With the event scheduled about halfway between the company's typical iPhone launches, the SE is rumored to replace the company's iPhone 5s with an improved device but at the same price.

Rendering of what iPhone SE could look like by MacRumors, used with permission.

The phone is expected to keep the 4-inch size of the iPhone 5s. This is smaller than the company's iPhone 6 and 6s devices, which have 4.7-inch displays. Internals, too, are expected to be upgraded. Among other expected improvements, the phone will reportedly adopt Apple's A9 processor currently in the iPhone 6 and 6 Plus.

A 9.7-inch iPad Pro: Rumors suggest Apple may introduce an iPad Air-sized iPad Pro.

What is an iPad Pro? Last November, Apple began selling its first iPad with a display larger than 9.7-inches, called an iPad Pro. Starting at $799, or $300 higher than the starting price of its iPad Air 2, the 12.9-inch device included significantly more utility than the iPad Air 2. For instance, the iPad Pro was compatible with the new Apple Pencil and Apple's Smart Keyboard.

This new iPad Pro could simply be a smaller version of its larger counterpart.

Apple Watch bands: Apple is also expected to introduce new Apple Watch bands. But with third-party sellers already crowding the market for Apple Watch bands, investors will likely be less interested in new band designs.

Apple Watch. Image source: Apple.

Potential (but unlikely) announcements
New Macs: As MacRumors notes, "the time is right for [Mac] updates, but there have been no rumors confirming that is the case."

But what about a new Apple Watch? With the event being just under a year after Apple began selling its Apple Watch, some investors might expect the company to introduce new versions of the smartwatch during the event. But the consensus in the ever-active Apple rumor mill is that Apple Watch hardware won't be updated until later this year.

Of course, Apple could introduce other products or services not listed here. The company is known for its secrecy and the tech giant likely tries to keep as much information about new products and services from the public eye as possible ahead of their debuts.

Further, even if the Apple rumor mill is right about Apple planning to introduce these products, plans could always change at the last minute.

The rumored iPhone SE will likely be the most important product for investors to watch. In Apple's most recent quarter, iPhone sales accounted for 68% of revenue. Any new product in this segment -- even if it's not a flagship device -- has potential to move the needle for the company.

Apple will be making a live stream of the event available online. Beginning at 10:00 AM PT on March 21, investors can watch the event at this page on Apple's website, or on Apple TV.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.