The Ring,piston, cataloged under National Stock Number 4310-00-331-2157, is classified within Federal Supply Class 4310 (Compressors and Vacuum Pumps) of the Pumps and Compressors group. The manufacturer of record is Dresser Industries Inc Leroi Div. 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 2 items share a part number with this NSN in the catalog (possible match — not a government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 | 4310-00-331-2157 |
| Primary Part Number | H18-540 |
| Item Name | Ring,piston |
| FSC / FSG | 4310 / 43 — Compressors and Vacuum Pumps |
| Manufacturer | Dresser Industries Inc Leroi Div |
| Status | ACTIVE |
| Cross-Sectional Shape Style | PLAIN RECTANGULAR, STRAIGHT FACE |
| Joint Style | VERTICAL JOINT |
| Radial Wall Thickness | 0.1120 INCHES NOMINAL IN |
| Ring Style | CONCENTRIC |
| Standard Bore Diameter | 2.500 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 |
|---|---|
| H18-540 PRIMARY | Dresser Industries Inc Leroi Div (USA) |
| Reference | Meaning |
|---|---|
| 903511 | 5/9 Secondary reference Dresser Industries Inc Leroi Div |
NSN 4310-00-331-2157 is a Ring,piston, manufactured by Dresser Industries Inc Leroi Div, classified under FSC 4310, Compressors and Vacuum Pumps. Status: active.
NSN 4310-00-331-2157 has 1 manufacturer part number on file: H18-540 (Dresser Industries Inc Leroi Div).
2 possible matches (shared part number, not a government interchangeability claim): 6145-01-676-7344, 6145-01-679-1788. Verify interchangeability with system specifications before substitution.
Key specifications for H18-540: Overall Width: 0.1250 INCHES NOMINAL IN; Cross-Sectional Shape Style: PLAIN RECTANGULAR, STRAIGHT FACE; Joint Style: VERTICAL JOINT; Radial Wall Thickness: 0.1120 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.