Apple's event is widely expected to feature the unveiling of 4.7" and 5.5" iPhone 6 models. Re/code reported yesterday a wearable device will also be shown off.
The invite shortly follows a Wired report stating the iPhone 6 will feature an NFC radio and support a new mobile payments platform. That meshes with past reports from VentureBeat, the WSJ, and others.
If history is any guide, the iPhone 6 will likely go on sale on Friday, Sep. 19, ten days after the launch event.
Update: MacRumors observes Apple has been building a giant hidden structure at the Flint Center, where the event will be held. The Flint Center is where Steve Jobs unveiled the Macintosh 30 years ago.