The Department of Defense, specifically the Department of the Navy through NAVSUP Weapon Systems Support, is seeking proposals for the procurement of 10 units of a flight-critical valve unit, identified by NSN 7R-1710-011820267-EY and reference number 538-104-1. The procurement requires that only sources previously approved by the Government be solicited, as the rights to use the necessary data for purchasing or repairing this part from additional sources are not owned by the Government, making reverse engineering uneconomical. Interested parties must submit their proposals along with the required source approval documentation, as offers lacking this information will not be considered; the deadline for submissions is 45 days from the notice publication date. For further inquiries, interested vendors can contact Kyle R. Matsinger at (215) 697-2995 or via email at KYLE.R.MATSINGER.CIV@US.NAVY.MIL.