The agency plans a long-term Indefinite Delivery Contract for a self-locking hexagon nut, with an estimated annual quantity of 1,600 units. The period of performance is a 5-year base with no option periods, and the contract will be issued under FAR Part 13.5 with Special Emergency Procurement Authorities. Approved sources are limited to GE Aviation Systems LLC and GE Aviation Systems Limited, with the acquisition unrestricted but using other than full and open competition. Delivery terms are FOB Origin with inspection and acceptance at origin, covering DLA Direct requirements only. This is an Air Force Critical Safety Item, and award may consider price, past performance, and other evaluation factors.