YubiKey 4 Nano
YubiKey 4 offers strong authentication via Yubico one-time passwords (OTP), FIDO Universal 2nd Factor (U2F), and smart card (PIV, OpenPGP, OATH-TOTP, and OATH-HOTP) — all with a simple touch of a button
Works instantly with no need to re-type passcodes — replacing SMS texts, authenticator apps, RSA tokens, and similar devices
Identifies as a USB keyboard, smart card, and smart card reader — no client software or drivers need to be installed, no batteries, no moving parts
Crush- and water-resistant, YubiKey 4 is practically indestructible during normal use — weighs only 3g, and attaches to your keychain alongside your house and car keys