From the notice

NSN 7R-1680-015677350-CB, IAW REF NR 71600-21817-101, QTY 9 EA, DELIVERY FOB ORIGIN. This part must be acquired from/repaired by a source(s)specified on a source control or selected item drawing as defined by thecurrent version of DoD-STD-100. Suitable technical data, Government data rights, or manufacturing/repair knowledge are not available to permit acquisition from/repair by other sources, nor qualification testing of another part, nor use of a second source part in the intended application. Although, by DoD-STD-100 definition, altered and selected items shall have an adequate technical data package, data review discloses that required data or data rights are not in Government possession and cannot be economically obtained.