The Department of Defense, specifically the Department of the Navy through NAVSUP Weapon Systems Support, is seeking proposals for the procurement of 53 units of a heat exchanger (NSN 7R-1660-015997646-QE). This procurement requires engineering source approval due to the flight-critical nature of the item, necessitating that only approved sources may submit proposals, as the technical data available does not support full and open competition. Interested parties must provide detailed documentation regarding their qualifications and experience in producing similar items, as well as comply with the source approval procedures outlined by the Government. Proposals must be submitted within 45 days of the notice, and any inquiries should be directed to Arianna G. Pilla at (215) 697-2198 or via email at ARIANNA.PILLA@NAVY.MIL.