Security Key by Yubico

The Security Key by Yubico combines hardware-based authentication, public key cryptography, and the U2F and FIDO2 protocols to eliminate account takeovers. It provides the strongest level of authentication to Twitter, Facebook, Gmail, GitHub, Dropbox, Dashlane, Salesforce, Duo, Centrify and hundreds more U2F and FIDO2 compatible services.

No additional software is required and authentication is easy, fast, and reliable. Simply insert the Security Key into a USB-A slot and authenticate with a simple touch.

It is strong first or second factor authentication that does not require a battery nor network connectivity so it is always on and accessible.