This is a non-competitive, sole-source solicitation for three flight-critical items, and only previously government-approved sources are being solicited directly. Unapproved sources must submit a full source approval package with their proposal, as the approval process is too lengthy to delay an award. The Government intends to negotiate with only one source, but it will consider proposals or capability statements received within 45 days from the publication of this notice for the purpose of possibly conducting a future competitive procurement. The delivery terms are FOB Origin. Interested parties may identify their capability to provide a commercial alternative within 15 days.