This is a sole-source solicitation for 18 units of a flight-critical part that requires existing Government source approval prior to contract award. The Government intends to negotiate only with previously approved sources, as the technical data and manufacturing knowledge are not economically available to support full and open competition. Unapproved sources may submit a proposal but must include a complete source approval request package with their offer. The Government will consider proposals received within 45 days of the synopsis publication for the purpose of determining whether to conduct a future competitive procurement. No specific budget, performance location, or non-bid/proposal timelines are detailed in this description.