Knowledge Base Frequently Asked Questions Basic Questions Search Where can I learn more about the YubiKey 4 and YubiKey 4 Nano? Where can I learn more about the YubiKey NEO and YubiKey NEO-n? Where can I learn more about the FIDO U2F Security Key? Why does the YubiKey 4 look exactly like the YubiKey Edge? How can I tell what version of YubiKey I have? How do I tell what type of key my Special Edition Octocat Key is? How do I store my YubiKey? What is two-factor authentication (2FA)? What is U2F? What is a One-Time Password (OTP)? Can I use my YubiKey with my PC? Can I use the YubiKey with my Mac? Can I use my YubiKey to log in to Windows? Is the YubiKey a biometric device? Do I need to install anything on my (or my user’s) computer to use the YubiKey? What is a YubiKey? Can I use the YubiKey with an iOS device (iPad, iPhone)? What lanyards can I use with my YubiKey? How can I buy a YubiKey? How can I purchase YubiKeys that are no longer on your web store? What is the warranty for my YubiKey? How do I get help for my YubiKey or apps? How can I perform batch programming of my YubiKeys?