The webcast will begin at 10 a.m. ET (7 a.m. PT), viewable to the public through a browser or from one of the company's Xbox video game consoles.
Microsoft issued invitations to analysts and the media three weeks ago, using the tease "We have some exciting news to share about Windows 10 devices."
Among the anticipated announcements and introductions: A replacement for 2014's Surface Pro 3, the company's own tablet-notebook, and a twosome of top-tier smartphones, the Lumia 950 and Lumia 950 X.
The Lumia handsets will be the first from Microsoft since it wrote off $7.6 billion -- and booked an associated $750 million to $850 million restructuring cost -- because of the failure of the Nokia acquisition to kick Windows smartphones into gear, and so will be worth watching.
In July, Microsoft CEO Satya Nadella recast the firm's smartphone strategy after the Nokia deal write-down, saying then that Microsoft would "run a more effective phone portfolio" and "narrow our focus."
Nadella called out three audiences whom he said Microsoft would address with smartphones that combine its own hardware with its own software -- Apple's iPhone model, as well as Google's more limited Nexus strategy -- listing business customers, cost-conscious buyers and Windows loyalists.
The Lumia 950 and Lumia 950 X are to fulfill Nadella's promise to offer the latter group new flagship devices.
Little concrete information has leaked about the possible Surface Pro 4, although most expect it to be slightly thinner, slightly lighter and likely somewhat faster than its predecessor, which has been the most successful of the devices in Microsoft's own 2-in-1 stable since it moved into the business three years ago.
The new Surface Pro will face more competition than its forerunner, and not from Microsoft's own OEMs (original equipment manufacturers): Apple will begin selling its 12.9-in. iPad Pro, a Surface-esque tablet that can also be partnered with a keyboard, next month. And Google has promised to put its 10.1-in. Pixel C on sale in time for this year's holidays.
Microsoft continues to discount the Surface Pro 3 on its online store, a back-on practice that hints at that model's termination. The current offer marks down the Surface Pro 3 by up to $150, representing discounts of between 8% and 13%.
Microsoft's Tuesday webcast can be accessed from the company's site.