The Government seeks five units of NSN 1R-5330-016951021-EY, reference 3890AS004816-01, delivered FOB origin. Contractual documents are deemed issued upon mailing, fax, or electronic transmission, and Government acceptance of a proposal creates a bilateral agreement; early and incremental deliveries are accepted. The action is intended as a sole-source procurement under FAR 6.302-1, with terms and conditions under an existing Basic Ordering Agreement. Responsible sources may identify their interest and capability or submit proposals, quotations, or capability statements, but this is not a request for competitive proposals. Military and federal specifications and standards are available through DODSSP and ASSIST-Online; the Government is not using FAR Part 12 commercial-item procedures, though interested parties may identify commercial-item interest and capability to the contracting officer.