This procurement is for NSN 7R-6120-014521359-KB, quantity 3, with delivery on an FOB origin basis. The item requires engineering source approval from the design control activity, and only government-approved sources have been solicited. Alternate sources must qualify through government-approved procedures, but the approval process typically cannot be completed in time for award. The government intends to solicit and negotiate with only one source under FAR 6.302-1, though all responsible sources may express interest and capability. The technical data and manufacturing knowledge essential to the part are retained by the approved source and not economically available to the government.