Note: This article lists the technical specifications of the Security Key C NFC. If you're looking for setup instructions for your Security Key C NFC, see https://www.yubico.com/start.
The Security Key C NFC provides the FIDO2 application as well as the U2F application, and can communicate using near-field communication (NFC), allowing for greater flexibility.
The Security Key C NFC uses a USB 2.0 interface as well as an NFC interface. All of the applications are available through both interfaces.
The U2F application can hold an unlimited number of U2F credentials and is FIDO certified.
The FIDO2 application allows for secure single and multi-factor authentication, and can store up to 25 resident credentials. These credentials, which are protected by a PIN, enable passwordless login, where the YubiKey, unlocked by a PIN and authorized by touch, can log you in to your accounts without entering a username or password. The FIDO2 application is FIDO certified.
To find out if an application is compatible with the Security Key C NFC, browse to the Works With YubiKey Catalog, and in YubiKey drop-down, select Security Key C NFC to only display services that are compatible with it.
Dimensions: 18mm x 45mm x 3.7mm
Operational range: 0 °C to 40 °C (32 °F to 104 °F)
Storage range: -20 °C to 85 °C (-4 °F to 185 °F)