NSN 4820-01-429-0556 — this item is cataloged by the U.S. Government under National Stock Number 4820-01-429-0556. Manufacturer of record part number: 556-6408987-A-6.
The Stem,fluid Valve, cataloged under National Stock Number 4820-01-429-0556, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Naval Sea Systems Command. Government technical data includes 5 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 6 items share a part number with this NSN in the catalog (possible match — not a government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
4820-01-429-0556
Primary Part Number
556-6408987-A-6
Item Name
Stem,fluid Valve
FSC / FSG
4820 / 48 — Valves, Nonpowered
Manufacturer
Naval Sea Systems Command
Status
ACTIVE
Valve Type for Which Designed
BALL
Stem Actuating End Type
THREADED EXTERNALLY
Features Provided
SPECIAL MARKING
Valve Size for Which Designed
0.500 INCHES IN
Material
COPPER ALLOY
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 Items6
Each row states its source: a government interchangeability/replacement code, or a possible match on a shared part number.
4820-01-429-1272556-6408987 FIND B-2POSSIBLE MATCH
CAP,VALVE
Possible match (shared part number)Naval Sea Systems Command
4820-01-429-1273556-6408987 FIND B-5POSSIBLE MATCH
SEAT,VALVE
Possible match (shared part number)Naval Sea Systems Command
4820-01-429-1276556-6408987 FIND B-6POSSIBLE MATCH
STEM,FLUID VALVE
Possible match (shared part number)Naval Sea Systems Command
4820-01-429-2492556-6408987 FIND B-4,B-5POSSIBLE MATCH
PARTS KIT,BALL VALVE
Possible match (shared part number)Naval Sea Systems Command
4730-01-432-9230264378701 FIND AA-1POSSIBLE MATCH
ADAPTER ASSEMBLY,VALVE
Possible match (shared part number)Naval Sea Systems Command
4820-01-442-3077264378701 FIND B-3POSSIBLE MATCH
PLUG,ROTARY,VALVE
Possible match (shared part number)Naval Sea Systems Command
NSN 4820-01-429-0556 is a Stem,fluid Valve, manufactured by Naval Sea Systems Command, classified under FSC 4820, Valves, Nonpowered. Status: active.
What part numbers are listed for NSN 4820-01-429-0556?
NSN 4820-01-429-0556 has 2 manufacturer part numbers on file: 211084952 (Naval Sea Systems Command), 556-6408987-A-6 (Naval Sea Systems Command).
What NSN replaces 4820-01-429-0556?
6 possible matches (shared part number, not a government interchangeability claim): 4820-01-429-1272, 4820-01-429-1273, 4820-01-429-1276. Verify interchangeability with system specifications before substitution.
What are the specifications of 556-6408987-A-6?
Key specifications for 556-6408987-A-6: Valve Type for Which Designed: BALL; Stem Actuating End Type: THREADED EXTERNALLY; Overall Length: 4.060 INCHES NOMINAL IN; Features Provided: SPECIAL MARKING. 5 specifications are documented in the U.S. Government catalog.
Is NSN 4820-01-429-0556 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.