This is a sources sought notice for market research to identify potential contractors capable of providing comprehensive maintenance, repair, and upgrade services for an extensive access control system. The required services include quarterly inspections and 24/7 on-call unscheduled maintenance, with a critical requirement to be on-site within one hour for high-severity issues at locations on Redstone Arsenal and Madison, Alabama. The anticipated period of performance is projected to be from July 2026 through December 2031, including a base year and several option periods. Interested vendors must demonstrate specific certifications as a Lenel OnGuard Federal Value-Added Reseller and with Avigilon systems, and confirm their employees will have a final DoD Secret clearance. The capability statement must also detail recent, relevant experience on US Army installations.