The Valve,check, cataloged under National Stock Number 4820-00-957-7865, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Tactair Fluid Controls Inc. Government technical data includes 23 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 2 items share a part number with this NSN in the catalog (possible match — not a government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 | 4820-00-957-7865 |
| Primary Part Number | 2528-6 |
| Item Name | Valve,check |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Tactair Fluid Controls Inc |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Surface Treatment Document and Classification | MIL-A-8625 MIL SPEC SINGLE TREATMENT RESPONSE |
| Connection Style | FLARELESS SECOND END |
| Connection Style | FLARED (TUBE) FIRST END |
| Connection Type | THREADED EXTERNAL TUBE FIRST END |
| Connection Type | THREADED EXTERNAL TUBE SECOND END |
| Style Designator | STRAIGHT THRU |
| Nominal Outside Diameter Tube Accommodated | 0.375 INCHES SECOND END IN |
| Thread Direction | RIGHT-HAND SECOND END |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 0.5625 INCHES SECOND END IN |
| Nominal Thread Size | 0.5625 INCHES FIRST END IN |
| Seat Angle | 45.0 DEGREES FIRST END |
| Seat Angle | 12.0 DEGREES SECOND END |
| Disk Loading Method | SPRING |
| Surface Treatment | ANODIZE |
| Thread Class | 3A FIRST END A |
| Thread Class | 3A SECOND END A |
| Thread Quantity Per Inch | 18 FIRST END |
| Thread Quantity Per Inch | 18 SECOND END |
| Thread Series Designator | UNF FIRST END |
| Thread Series Designator | UNF SECOND END |
| 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 |
|---|---|
| 2528-6 PRIMARY | Tactair Fluid Controls Inc (USA) |
| Reference | Meaning |
|---|---|
| 2528-6 | 5/9 Secondary reference U.S. Government activity |
| 2528-6 | 5/9 Secondary reference U.S. Government activity |
NSN 4820-00-957-7865 is a Valve,check, manufactured by Tactair Fluid Controls Inc, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-00-957-7865 has 1 manufacturer part number on file: 2528-6 (Tactair Fluid Controls Inc).
2 possible matches (shared part number, not a government interchangeability claim): 6210-01-104-6023, 5940-01-244-6666. Verify interchangeability with system specifications before substitution.
Key specifications for 2528-6: Flow Control Device: POPPET; Surface Treatment Document and Classification: MIL-A-8625 MIL SPEC SINGLE TREATMENT RESPONSE; Connection Style: FLARELESS SECOND END; Connection Style: FLARED (TUBE) FIRST END. 23 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.