Presolicitation notice from the Department of Defense, Department of the Navy, for the procurement of a diplexer. A diplexer is a device used in communication systems to combine or separate different frequency bands. This specific diplexer, NSN 7R-5985-014373108-FW, is required in a quantity of 4 EA and must be delivered FOB origin. The part requires engineering source approval from the design control activity to maintain its quality. Only approved sources have been solicited for this item, as it is flight critical and the technical data available is not determined adequate for full and open competition. Interested parties must submit the necessary information for source approval. Failure to provide all required data will result in disqualification.