The Ring,retaining, cataloged under National Stock Number 5325-01-351-5134, is classified within Federal Supply Class 5325 (Fastening Devices) of the Hardware and Abrasives group. The manufacturer of record is Caterpillar Inc Div Caterpillar Defense. Government technical data includes 8 specifications, cited from the U.S. Government catalog. The record lists 3 manufacturer part numbers 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5325-01-351-5134 |
| Primary Part Number | 4N7521 |
| Item Name | Ring,retaining |
| FSC / FSG | 5325 / 53 — Fastening Devices |
| Manufacturer | Caterpillar Inc Div Caterpillar Defense |
| Status | ACTIVE |
| Usage Design | EXTERNAL |
| End Style | VERTEX CENTER OR ABOVE |
| Cross-Sectional Shape Style | RECTANGULAR |
| Major Thickness | 0.102 INCHES NOMINAL IN |
| Inside Diameter | 0.669 INCHES NOMINAL IN |
| Casehardening Indicator | NOT CASEHARDENED |
| Ring Style | STRAIGHT GAP |
| Material | STEEL |
| 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 |
|---|---|
| 4N7521 PRIMARY | Caterpillar Inc Div Caterpillar Defense (USA) |
| 4N7521 | Texas Marine and Industrial Supply Co (USA) |
| 4N7521 | Alban Tractor, Llc (USA) |
| Reference | Meaning |
|---|---|
| 4N7521 | 5/9 Secondary reference Giles and Ransome Inc Ransome Engine Power Div |
| 4N7521 | 5/9 Secondary reference Holt Bros |
NSN 5325-01-351-5134 is a Ring,retaining, manufactured by Caterpillar Inc Div Caterpillar Defense, classified under FSC 5325, Fastening Devices. Status: active.
NSN 5325-01-351-5134 has 3 manufacturer part numbers on file: 4N7521 (Caterpillar Inc Div Caterpillar Defense), 4N7521 (Texas Marine and Industrial Supply Co), 4N7521 (Alban Tractor, Llc).
Key specifications for 4N7521: Usage Design: EXTERNAL; End Style: VERTEX CENTER OR ABOVE; Cross-Sectional Shape Style: RECTANGULAR; Major Thickness: 0.102 INCHES NOMINAL IN. 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.