The requirement is for 20 pairs of NSN 3H-3110-009921016-NT under TDP version 007, delivered FOB origin. The part requires engineering source approval by the design control activity to maintain quality. Approved sources retain data rights, manufacturing/repair knowledge, or technical data not economically available to the Government that are essential to quality. Alternate sources must qualify under the design control activity’s procedures, as approved by the cognizant Government engineering activity with jurisdiction over the intended application. The Government is not using FAR Part 12 commercial-item policies, though interested parties may identify commercial-item interest and capability to the contracting officer.