Apple and Amazon.com have now unveiled or released each of their respective fall product lineups. The Mac maker kicked off September by introducing the iPhone 6s and 6s Plus, iPad Pro, and a new Apple TV. Amazon then fired back with new Kindle Fire tablets and new Fire TV devices while quietly bowing out of the smartphone market.

Now, Google (GOOG -0.46%) (GOOGL -0.54%) has sent invites to a Sept. 29 event. It's the search giant's turn to take the stage to unveil new stuff. Here's what investors can expect.

New Nexuses
Google is expected to launch two new Nexus flagship phones, dubbed the Nexus 5X and Nexus 6P, according to Droid Life. As usual, Google is tapping different smartphone manufacturers, as it likes to rotate partners each year. This time around we're talking about LG and Huawei. LG is making the 5-inch Nexus 5X, while Huawei is making the Nexus 6P. It's not clear what the "X" and "P" monikers are for.

LG is a longtime Nexus partner and has made many a Nexus device, but Huawei is new to the mix. Considering Huawei's precipitous rise in the smartphone industry (Huawei's shipments jumped 48% last quarter to make it the No. 3 vendor globally), the Chinese OEM's addition makes sense. Huawei's model will reportedly be the first Nexus phone with 128GB of onboard storage.

With fingerprint sensors being all the rage these days in modern smartphones, both models are expected to incorporate them. Android Marshmallow is the first version of the popular operating system to include first-party support for integrated fingerprint sensors. Google is also expected to release Android Marshmallow to the masses around this time as well, even though fragmentation inevitably limits how quickly users can upgrade to the latest and greatest 6.0 version.

New Chromecast
Seeing as how Apple and Amazon are now focusing efforts on streaming media devices, it should come as no surprise that Google will follow suit with a new version of its popular Chromecast streaming dongle. The second-generation model is getting a circular redesign along with a handful of other features. The main screen will include various content feeds, and the device will get faster Wi-Fi and a new feature called "Fast Play," according to 9to5Google.

The streaming wars are only going to continue heating up, which will lead to more choice for consumers. That's a good thing.

Ironically, Chromecast is arguably more important in some ways than Nexus, even though the smartphone market utterly dwarfs the streaming media device market. Nexus devices have never been huge sellers in terms of volume; they're primarily done to set an example of what a "pure" Android device can be so that there is a baseline of expectations.

Chromecast, on the other hand, has soared to the No. 2 spot by market share in 2014, according to Parks Associates, thanks to its attractive $35 price point. Put another way, Nexus is a sliver of a large but mature market, while Chromecast is a leading force in a small but growing one.

It's not over yet
After Google's event, Microsoft will step up to the plate to take a swing at some product unveilings. The event is slated for Oct. 6 and a Surface Pro 4 is almost undoubtedly incoming. It's going to be a busy fall for product unveilings.