Authenticator for Android is used by millions of users and, combined with 2-Step Verification, it provides an extra layer of protection for Google Accounts.
Our latest version has some cool new features. You will notice a new icon and a refreshed design. There's also support for Android Wear devices, so you'll be able to get verification codes from compatible devices, like your watch.
Developers who want to learn more about U2F can refer to FIDO's specifications. Additionally, you can try it out at https://u2fdemo.appspot.com. Note that you'll need an Android device running the latest versions of Google Chrome and Authenticator and also a Security Key with NFC support.
You can find the latest Authenticator for Android on the Play Store.