The Valve,nonreturn, cataloged under National Stock Number 4820-00-402-5452, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Imi Norgren Sales Ltd. Government technical data includes 1 specification, 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. 1 item shares a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-00-402-5452 |
| Primary Part Number | C521 |
| Item Name | Valve,nonreturn |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Imi Norgren Sales Ltd |
| Status | ACTIVE |
| General Characteristics Item Description | 100 PSI RATED |
| 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 |
|---|---|
| C521 PRIMARY | Imi Norgren Sales Ltd (GBR) |
NSN 4820-00-402-5452 is a Valve,nonreturn, manufactured by Imi Norgren Sales Ltd, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-00-402-5452 has 1 manufacturer part number on file: C521 (Imi Norgren Sales Ltd).
1 possible match (shared part number, not a government interchangeability claim): 5950-01-278-7090. Verify interchangeability with system specifications before substitution.
Key specifications for C521: General Characteristics Item Description: 100 PSI RATED. 1 specification is 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.