The Breech,door, cataloged under National Stock Number 4540-01-220-2143, is classified within Federal Supply Class 4540 (Waste Disposal Equipment) of the Plumbing, Heating, and Waste Disposal group. The manufacturer of record is Naval Inventory Control Point Mechanicsburg. Government technical data includes 2 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through both NSN and commercial part number lookups. 4 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4540-01-220-2143 |
| Primary Part Number | 77656-31X3 PIECE1L1 |
| Item Name | Breech,door |
| FSC / FSG | 4540 / 45 — Waste Disposal Equipment |
| Manufacturer | Naval Inventory Control Point Mechanicsburg |
| Status | ACTIVE |
| Criticality Code Justification | ZZZY |
| Reference Number Differentiating Characteristics | QUALITY CONTROL IN ACCORDANCE WITH NAVSHIPS 0948-045-7010 MATERIAL IDENTIFICATION AND CONTROL INSTRUCTION FOR LEVEL 1 ITEMS |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | S |
| Part Number | Manufacturer |
|---|---|
| 77656-31X3 PIECE1L1 | Naval Inventory Control Point Mechanicsburg (USA) |
| SSN637-505-21439L1 | Naval Inventory Control Point Mechanicsburg (USA) |
| Reference | Meaning |
|---|---|
| SSN637-505-2143921 PIECE 1L1 | 5/1 Secondary reference Naval Inventory Control Point Mechanicsburg |
| 77656-31X3 PIECE1 | 3/1 Design control — primary reference U.S. Government activity |
| SSN637-505-2143921 PIECE 1 | 5/1 Secondary reference U.S. Government activity |
| SSN637-505-21439 | 5/1 Secondary reference U.S. Government activity |
NSN 4540-01-220-2143 is a Breech,door, manufactured by Naval Inventory Control Point Mechanicsburg, classified under FSC 4540, Waste Disposal Equipment. Status: active.
NSN 4540-01-220-2143 has 2 manufacturer part numbers on file: 77656-31X3 PIECE1L1 (Naval Inventory Control Point Mechanicsburg), SSN637-505-21439L1 (Naval Inventory Control Point Mechanicsburg).
Key specifications for 77656-31X3 PIECE1L1: Criticality Code Justification: ZZZY; Reference Number Differentiating Characteristics: QUALITY CONTROL IN ACCORDANCE WITH NAVSHIPS 0948-045-7010 MATERIAL IDENTIFICATION AND CONTROL INSTRUCTION FOR LEVEL 1 ITEMS. 2 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.