Google announced the release of its Titan Security Key, a physical device used as an additional authentication method on devices.  The Titan Security Key is built according to FIDO Alliance specifications and will be available soon at the Google Store.

Google released more technical details on how the new security key works at https://cloudplatform.googleblog.com/2017/08/Titan-in-depth-security-in-plaintext.html.

Update:  the Titan Security Key is now available at https://store.google.com/product/titan_security_key_kit.

Setup for Google account two factor authentication can be done at https://www.google.com/landing/2step/.