The Ring,piston, cataloged under National Stock Number 2815-00-736-8397, is classified within Federal Supply Class 2815 (Diesel Engines and Components) of the Engines, Turbines, and Components group. The manufacturer of record is Cooper Machinery Services Llc. Government technical data includes 6 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 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 | 2815-00-736-8397 |
| Primary Part Number | B-4781 |
| Item Name | Ring,piston |
| FSC / FSG | 2815 / 28 — Diesel Engines and Components |
| Manufacturer | Cooper Machinery Services Llc |
| Status | ACTIVE |
| Cross-Sectional Shape Style | PLAIN RECTANGULAR, STRAIGHT FACE |
| Joint Style | VERTICAL JOINT |
| Radial Wall Thickness | 0.2812 INCHES NOMINAL IN |
| Ring Style | CONCENTRIC |
| Standard Bore Diameter | 8.000 INCHES IN |
| Material | STEEL OVERALL |
| 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 |
|---|---|
| B-4781 PRIMARY | Cooper Machinery Services Llc (USA) |
NSN 2815-00-736-8397 is a Ring,piston, manufactured by Cooper Machinery Services Llc, classified under FSC 2815, Diesel Engines and Components. Status: active.
NSN 2815-00-736-8397 has 1 manufacturer part number on file: B-4781 (Cooper Machinery Services Llc).
1 possible match (shared part number, not a government interchangeability claim): 6680-00-966-9476. Verify interchangeability with system specifications before substitution.
Key specifications for B-4781: Overall Width: 0.1875 INCHES NOMINAL IN; Cross-Sectional Shape Style: PLAIN RECTANGULAR, STRAIGHT FACE; Joint Style: VERTICAL JOINT; Radial Wall Thickness: 0.2812 INCHES NOMINAL IN. 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.