The Washer,flat, cataloged under National Stock Number 5310-00-291-9737, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Tyco Fire Products Lp. Government technical data includes 6 specifications, cited from the U.S. Government catalog. The record lists 2 manufacturer part numbers 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 | 5310-00-291-9737 |
| Primary Part Number | S561 |
| Item Name | Washer,flat |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Tyco Fire Products Lp |
| Status | ACTIVE |
| Overall Diameter | 1.344 INCHES NOMINAL IN |
| Cross-Sectional Shape Style | RECTANGULAR |
| Peripheral Shape Style | ROUND |
| Center Hole Shape Style | ROUND |
| Hole Diameter | 1.000 INCHES NOMINAL IN |
| Thickness | 0.188 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 |
NSN 5310-00-291-9737 is a Washer,flat, manufactured by Tyco Fire Products Lp, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-00-291-9737 has 2 manufacturer part numbers on file: S561 (Tyco Fire Products Lp), S927PC20 (Tyco Fire Products Lp).
1 possible match (shared part number, not a government interchangeability claim): 5930-01-621-3528. Verify interchangeability with system specifications before substitution.
Key specifications for S561: Overall Diameter: 1.344 INCHES NOMINAL IN; Cross-Sectional Shape Style: RECTANGULAR; Peripheral Shape Style: ROUND; Center Hole Shape Style: ROUND. 6 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.