The Diaphragm,valve,flat, cataloged under National Stock Number 4820-00-678-0261, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Mechanical Rubber Products Company, Inc. Dba Mechanical Rubber Prdts Co Inc Div Mechanical Rubber Products Co., Inc.. Government technical data includes 8 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government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 | 4820-00-678-0261 |
| Primary Part Number | MR57 |
| Item Name | Diaphragm,valve,flat |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Mechanical Rubber Products Company, Inc. Dba Mechanical Rubber Prdts Co Inc Div Mechanical Rubber Products Co., Inc. |
| Status | ACTIVE |
| Outside Diameter | 4.844 INCHES NOMINAL IN |
| Style Designator | FLAT |
| Material Thickness | 0.025 INCHES NOMINAL IN |
| Bolt Hole Quantity | 1 |
| Bolt Circle Diameter | 4.344 INCHES NOMINAL IN |
| Center Hole Diameter | 0.203 INCHES NOMINAL IN |
| Material | RUBBER SYNTHETIC |
| Hole Diameter | 0.203 INCHES NOMINAL IN |
| 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 |
|---|---|
| MR57 PRIMARY | Mechanical Rubber Products Company, Inc. Dba Mechanical Rubber Prdts Co Inc Div Mechanical Rubber Products Co., Inc. (USA) |
| Reference | Meaning |
|---|---|
| 1791-25 | 5/9 Secondary reference General Regulator Corp. Dba Accudriv |
NSN 4820-00-678-0261 is a Diaphragm,valve,flat, manufactured by Mechanical Rubber Products Company, Inc. Dba Mechanical Rubber Prdts Co Inc Div Mechanical Rubber Products Co., Inc., classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-00-678-0261 has 1 manufacturer part number on file: MR57 (Mechanical Rubber Products Company, Inc. Dba Mechanical Rubber Prdts Co Inc Div Mechanical Rubber Products Co., Inc.).
1 possible match (shared part number, not a government interchangeability claim): 4130-01-211-6507. Verify interchangeability with system specifications before substitution.
Key specifications for MR57: Outside Diameter: 4.844 INCHES NOMINAL IN; Style Designator: FLAT; Material Thickness: 0.025 INCHES NOMINAL IN; Bolt Hole Quantity: 1. 8 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.