This is a market research Sources Sought notice for the potential future modernization of the D-21 Fire Alarm System at Ellsworth Air Force Base, South Dakota, which includes a required post-upgrade site visit. The purpose is to identify capable and interested contractors for a possible future solicitation. Capability statements from interested parties are due by 1:00 PM MST on January 10, 2026. No budget information is specified in this notice. This is not a request for proposals, and no contract will be awarded from this action.