A unique string of characters provided by the manufacturer (SAi) upon purchase.
Be aware that a password for version 10.0 might not work for 10.5.1, as the latter often requires an updated license string. Modern Security: Why Use 1Password with Flexi? Flexisign Pro 10.5 1 Password
Because Flexi 10.5.1 is an older version of the software, it is optimized for older environments: A unique string of characters provided by the