The Stem,needle Valve, cataloged under National Stock Number 4820-01-444-2590, 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 4 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through both NSN and commercial part number lookups. 4 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 3 items share a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-444-2590 |
| Primary Part Number | 556-6406600-MVSA-B6 |
| Item Name | Stem,needle Valve |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Naval Sea Systems Command |
| Status | ACTIVE |
| Largest Outside Diameter | 0.736 INCHES NOMINAL IN |
| Stem Actuating End Type | THREADED EXTERNALLY |
| Material Document and Classification | ASTM 8150 UNS C63200 ASSN STD SINGLE MATERIAL RESPONSE |
| Material | COPPER ALLOY |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| 556-6406600-MVSA-B6 PRIMARY | Naval Sea Systems Command (USA) |
| 556-6406600-MVSA-A6 PRIMARY | Naval Sea Systems Command (USA) |
| Reference | Meaning |
|---|---|
| 556-6406600-MVSA-A6 | 5/2 Secondary reference U.S. Government activity |
| 218013125 | 5/2 Secondary reference U.S. Government activity |
| 218013125 | C/1 Advisory reference — outside the item-of-supply concept Naval Sea Systems Command |
| 6406600 | D/9 Drawing number reference only Naval Sea Systems Command |
NSN 4820-01-444-2590 is a Stem,needle Valve, manufactured by Naval Sea Systems Command, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-444-2590 has 2 manufacturer part numbers on file: 556-6406600-MVSA-B6 (Naval Sea Systems Command), 556-6406600-MVSA-A6 (Naval Sea Systems Command).
3 possible matches (shared part number, not a government interchangeability claim): 4820-01-444-4313, 4820-01-444-4317, 4820-01-444-5647. Verify interchangeability with system specifications before substitution.
Key specifications for 556-6406600-MVSA-B6: Largest Outside Diameter: 0.736 INCHES NOMINAL IN; Stem Actuating End Type: THREADED EXTERNALLY; Material Document and Classification: ASTM 8150 UNS C63200 ASSN STD SINGLE MATERIAL RESPONSE; Overall Length: 4.730 INCHES NOMINAL IN. 4 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
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.