The Valve,safety Relief, cataloged under National Stock Number 4820-01-273-0491, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Concentric Rockford Inc. Government technical data includes 2 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 2 items share a part number with this NSN in the catalog (possible match — not a government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 | 4820-01-273-0491 |
| Primary Part Number | 1300021 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Concentric Rockford Inc |
| Status | ACTIVE |
| Adjustable Pressure Range | +1000.0 TO 1500.0 POUNDS PER SQUARE INCH LBS |
| Valve Operation Method | AUTOMATIC |
| 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 |
|---|---|
| 1300021 PRIMARY | Concentric Rockford Inc (USA) |
| Reference | Meaning |
|---|---|
| 2300195 | 5/9 Secondary reference Concentric Rockford Inc |
| P-3031 | 5/9 Secondary reference Lift Truck Service Co |
NSN 4820-01-273-0491 is a Valve,safety Relief, manufactured by Concentric Rockford Inc, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-273-0491 has 1 manufacturer part number on file: 1300021 (Concentric Rockford Inc).
2 possible matches (shared part number, not a government interchangeability claim): 3439-01-364-0870, 5955-01-403-2809. Verify interchangeability with system specifications before substitution.
Key specifications for 1300021: Adjustable Pressure Range: +1000.0 TO 1500.0 POUNDS PER SQUARE INCH LBS; Valve Operation Method: AUTOMATIC. 2 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.