National Stock Number
2990-00-438-1551
National Stock Number (NSN) 2990-00-438-1551, or NIIN 004381551, (cap assembly,protective,muffler-) was assigned September 10, 1969 in the Federal Logistics Information System (FLIS). This NIIN is Available for Manual Assignment. This NSN replaces 16 stock numbers. Five of the National Stock Numbers that it replaces are: 2990008707840, 2990003731528, 2990001856904, 2990008521195, 2990009061870.
There are 32 manufacturer part numbers associated with this NSN. 15 of those part number(s) are considered obsolete. The manufacturer part numbers were originally supplied by 32 suppliers. Today, 21 suppliers are listed as Active suppliers for this NSN. Of the active suppliers, 13 suppliers are deemed design controlled or valid supply parts. ISO Group has several sources of supply for this NSN.
This part number has not been procured by the US Government in over 5 years.
This NSN is very common among different weapons systems, belonging to 37 different platforms.
Based on a planned procurement review by the Primary Inventory Control Activity (PICA) on Nov 22, 2012, this NSN's acquisition method was noted as: Suitable for Competitive Acquisition. (Potential sources shall include dealers/distributors.) The data or the rights to use the data needed to purchase this part from additional sources are not owned by the Government and it has been determined that it is uneconomical to purchase them. Valid AMCs: 1, 2, 3, 4 and 5.
This NSN is assigned to Item Name Code (INC) 61446. [AN ITEM DESIGNED TO FIT OVER THE OPENING OF AN ENGINE EXHAUST PIPE OR MUFFLER TO PREVENT THE ENTRANCE OF RAIN OR FOREIGN MATTER INTO THE MANIFOLD SECTION OF A RECIPROCATING ENGINE WHILE NOT IN USE. IT IS AUTOMATICALLY OPENED WHEN THE ENGINE IS STARTED BY PRESSURE EXERTED FROM THE EXHAUST SYSTEM. IT IS EQUIPPED WITH A HINGING ACTION AND MAY OR MAY NOT HAVE A COUNTER WEIGHT. EXCLUDES CAP, PROTECTIVE, DUST AND MOISTURE SEAL.]. This item does not have a nuclear hardened feature or any other critical feature such as tolerance, fit restriction or application. There is no data in the HMIRS and the NSN is in an FSC not generally suspected of containing hazardous materials. NSN 2990004381551 does not contain precious metals.
This NSN is associated to Schedule B 8412909080: parts of engines and motors, nesoi. The Schedule B End Use is listed as industrial engines. NAICS classification category 333111: farm machinery and equipment manufacturing.
This information was last updated on Aug 01, 2025.