After being unveiled in October, today marks the official launch of Google Wifi. Google Wifi is Google's second attempt at a Wi-Fi router, after the Google OnHub released last year.
The new feature for "Google router version 2" is mesh networking, while the OnHub's promised-but-never-delivered smart home features are dropped. You can buy multiple Google Wifis, and they'll all mesh together, offering (hopefully) better coverage than a single device. Google is pushing the mesh capabilities heavily with a $299 "3-pack" option or $129 for a single device. Google Wifi has a lot in common with the OnHub. Existing OnHub users will be able to add OnHub to a Google Wifi mesh network, and the OnHub app has already been renamed "Google Wifi" on the Play Store.
You should be able to run out and buy Google Wifi from Best Buy or Walmart today, with online orders through the Google Store and Amazon shipping now. We'll have a review of Google Wi-Fi out soon, in which we'll compare it to other mesh Wi-Fi solutions.