NSN 4820-00-308-9889 — this item is cataloged by the U.S. Government under National Stock Number 4820-00-308-9889. Manufacturer of record part number: 9491-21-1.
The Seat,valve, cataloged under National Stock Number 4820-00-308-9889, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Fluidyne Corporation Dba Fluidyne Corp. Government technical data includes 7 specifications, cited from the U.S. Government catalog. The record lists 2 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 4 items share a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
Technical Specifications
Parameter
Value
NSN
4820-00-308-9889
Primary Part Number
9491-21-1
Item Name
Seat,valve
FSC / FSG
4820 / 48 — Valves, Nonpowered
Manufacturer
Fluidyne Corporation Dba Fluidyne Corp
Status
ACTIVE
Body Outside Diameter
4.938 INCHES NOMINAL IN
Style Designator
PLAIN
Body Inside Diameter
4.312 INCHES NOMINAL IN
Surface Treatment
PAINT OVERALL
Material
STEEL OVERALL
Seat Angle in Deg
45.000 NOMINAL
Seating Surface Shape
ANGULAR
Lifecycle & Compliance
Acquisition Status
ACTIVE
DEMIL Code
DEMIL A — No Demilitarization Required
Hazard
No hazard code in the DLA record (HMIC N)
Criticality Code
X
⇄Related Items4
Each row states its source: a government interchangeability/replacement code, or a possible match on a shared part number.
1377-00-980-7357POSSIBLE MATCH
FIRING DEVICE,EXPLOSIVE LEAD
Possible match (shared part number)
5330-01-117-0174POSSIBLE MATCH
GASKET,PRESSURE
Possible match (shared part number)
5935-01-125-0946PL93-3POSSIBLE MATCH
CONNECTOR,PLUG,ELECTRICAL
Possible match (shared part number)Trompeter Electronics, Inc.
5805-01-503-7482437-7068236-199POSSIBLE MATCH
KEYPAD,TELEPHONE
Possible match (shared part number)Naval Sea Systems Command
NSN 4820-00-308-9889 is a Seat,valve, manufactured by Fluidyne Corporation Dba Fluidyne Corp, classified under FSC 4820, Valves, Nonpowered. Status: active.
What part numbers are listed for NSN 4820-00-308-9889?
NSN 4820-00-308-9889 has 2 manufacturer part numbers on file: 9491-21-1 (Fluidyne Corporation Dba Fluidyne Corp), 9491-21-1 (The Walworth Company).
What NSN replaces 4820-00-308-9889?
4 possible matches (shared part number, not a government interchangeability claim): 1377-00-980-7357, 5330-01-117-0174, 5935-01-125-0946. Verify interchangeability with system specifications before substitution.
What are the specifications of 9491-21-1?
Key specifications for 9491-21-1: Overall Height: 0.625 INCHES NOMINAL IN; Body Outside Diameter: 4.938 INCHES NOMINAL IN; Style Designator: PLAIN; Body Inside Diameter: 4.312 INCHES NOMINAL IN. 7 specifications are documented in the U.S. Government catalog.
Is NSN 4820-00-308-9889 hazardous material?
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
Sources
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.
✓ Data cited from the U.S. Government catalog; commercial cross-references from OEM and certified industry sources.