The Hose,air Duct,air Breathing, cataloged under National Stock Number 4240-01-421-3666, is classified within Federal Supply Class 4240 (Safety and Rescue Equipment) of the Fire Fighting, Rescue, and Safety Equipment group. The manufacturer of record is E. D. Bullard Company Dba Ed Bullard Co. 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 2 items share a part number with this NSN in the catalog (possible match — not a government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 | 4240-01-421-3666 |
| Primary Part Number | BT100 |
| Item Name | Hose,air Duct,air Breathing |
| FSC / FSG | 4240 / 42 — Safety and Rescue Equipment |
| Manufacturer | E. D. Bullard Company Dba Ed Bullard Co |
| Status | ACTIVE |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | Possible hazard — SDS may be required (DLA HMIC P) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| BT100 PRIMARY | E. D. Bullard Company Dba Ed Bullard Co (USA) |
| Reference | Meaning |
|---|---|
| B100 | 5/9 Secondary reference E. D. Bullard Company Dba Ed Bullard Co |
NSN 4240-01-421-3666 is a Hose,air Duct,air Breathing, manufactured by E. D. Bullard Company Dba Ed Bullard Co, classified under FSC 4240, Safety and Rescue Equipment. Status: active.
NSN 4240-01-421-3666 has 1 manufacturer part number on file: BT100 (E. D. Bullard Company Dba Ed Bullard Co).
2 possible matches (shared part number, not a government interchangeability claim): 6920-01-467-7374, 6650-01-608-7017. Verify interchangeability with system specifications before substitution.
Key specifications for BT100: Special Features: 0.250 IN. INDUSTRIAL INTERCHANGE FITTING; BREATHING TUBE WITH ADJUSTABLE FLOW VALVE; SOLE SOURCE REQUIRED BY STATUTE 6.302; COMPONENT OF NIOSH APPROVAL TC-19C-322 AND 321 IN; End Item Identification: RESPIRATOR, E.D. BULLARD COMPANY; SERIES M45. 0 specifications are documented in the U.S. Government catalog.
Possible hazard — SDS may be required (DLA HMIC P). 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.