The Retainer,disk,valve, cataloged under National Stock Number 4820-01-491-6489, 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 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 3 items share a part number with this NSN in the catalog (possible match — not a government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 | 4820-01-491-6489 |
| Primary Part Number | 566-6985434-11 |
| Item Name | Retainer,disk,valve |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Naval Sea Systems Command |
| Status | ACTIVE |
| Outside Diameter | 1.125 INCHES NOMINAL IN |
| Nominal Thread Size | 1.125 INCHES IN |
| Valve Size for Which Designed | 1.250 INCHES IN |
| Valve Design Control Activity | 53711 |
| Material | NICKEL 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 |
|---|---|
| 566-6985434-11 | Naval Sea Systems Command (USA) |
| Reference | Meaning |
|---|---|
| H623-0507-11 | 5/9 Secondary reference U.S. Government activity |
| H6230507A-11 | 3/2 Design control — primary reference U.S. Government activity |
| 566-6985434 | D/9 Drawing number reference only Naval Sea Systems Command |
NSN 4820-01-491-6489 is a Retainer,disk,valve, manufactured by Naval Sea Systems Command, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-491-6489 has 1 manufacturer part number on file: 566-6985434-11 (Naval Sea Systems Command).
3 possible matches (shared part number, not a government interchangeability claim): 4820-01-491-6495, 5340-01-671-4932, 2810-01-733-3366. Verify interchangeability with system specifications before substitution.
Key specifications for 566-6985434-11: Outside Diameter: 1.125 INCHES NOMINAL IN; Overall Length: 3.500 INCHES NOMINAL IN; Nominal Thread Size: 1.125 INCHES IN; Valve Size for Which Designed: 1.250 INCHES IN. 5 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.