The Department of Defense, through the Department of the Navy's NAVSUP Weapon Systems Support, is seeking to procure three units of the 16--100 W Filter PA, Air, under a presolicitation notice. This procurement requires engineering source approval due to the flight-critical nature of the item, necessitating that all proposals include detailed documentation demonstrating compliance with the source approval requirements. The selected source must possess unique design capabilities and manufacturing knowledge essential for maintaining the quality of the part, as the government intends to solicit and negotiate with only one approved source under FAR 6.302-1. Interested parties must submit their proposals within 45 days of the notice publication, and for further inquiries, they can contact Kelly A. Gipson at (215) 697-4787 or via email at KELLY.A.GIPSON1@NAVY.MIL.