Note: This article lists the technical specifications of the Security Key by Yubico. If you're looking for setup instructions for your Security Key, see https://www.yubico.com/start.
The Security Key by Yubico provides the FIDO2 application as well as the U2F application, allowing for greater flexibility.
Interface
The Security Key by Yubico uses a USB 2.0 interface. All applications are available over this interface.
Applications
U2F
The U2F application can hold an unlimited number of U2F credentials and is FIDO certified.
FIDO2
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 by Yubico, browse to the Works With YubiKey Catalog, and in YubiKey drop-down, select Security Key by Yubico to only display services that are compatible with it.
Physical Specifications
Form Factor
Connector: USB-A
Dimensions: 18mm x 45mm x 3.3mm
Weight: 3g
Temperatures
Operational range: 0 °C to 40 °C (32 °F to 104 °F)
Storage range: -20 °C to 85 °C (-4 °F to 185 °F)