Add advanced security services to a qualifying Microsoft 365 F5 Government Community Cloud environment with an annual user subscription. Microsoft E521B79055BC-1Y provides the GCC-specific M365 F5 Security Add-on entitlement for 1 year, extending a frontline-worker productivity environment with Microsoft security capabilities across identities, endpoints, email, collaboration, and cloud applications. This add-on fits organizations that run Microsoft 365 F5 user subscriptions in GCC and need a higher security tier without changing the underlying productivity plan. Its coverage areas support common security operations such as identifying risky sign-in activity, protecting managed endpoints, screening email and collaboration activity, and monitoring cloud-app use. The subscription is intended to be assigned alongside eligible Microsoft 365 F5 licensing rather than deployed as standalone desktop software or an appliance. GCC scope is a defining characteristic of this specific subscription: it is intended for Microsoft 365 Government Community Cloud tenant environments. The 1-year term also distinguishes this ordering code from subscription terms that may be offered separately. Choose this add-on when the requirement is to extend an existing M365 F5 deployment with the F5 security service tier while retaining GCC tenant alignment.