The Department of Defense, through the NAVSUP Weapon Systems Support office, is seeking competitive proposals for the procurement of five modulating valves, specifically NSN 7R-1660-011618379-VH, under part number 321025. These valves are critical components used in aircraft air conditioning, heating, and pressurizing systems, and the procurement will follow the guidelines set forth in FAR Part 13, excluding the policies for commercial items. Interested vendors must be approved sources, specifically MEGGITT-PARKER CORPORATION and SIKORSKY AIRCRAFT CORPORATION, and those not already approved must submit a Source Approval Request (SAR) without delaying the procurement process. Proposals are due within 45 days of this notice, and interested parties should direct their inquiries and submissions to Danielle M. Cutrera at Danielle.Cutrera@navy.mil.