PartsTable TECHNICAL DATA SHEET

NSN 4520-00-237-5261Government record, cited

Reducer, Flue Pipe4520-00-237-5261

NSN 4520-00-237-5261 · NIIN 002375261 · Part number 6X4BTR

Masco Corp American Metal Products Co Div · FSC 4520 — Space and Water Heating Equipment · FSG 45 — Plumbing, Heating, and Waste Disposal · CAGE 34557

Government record, cited

NSN 4520-00-237-5261 — this item is cataloged by the U.S. Government under National Stock Number 4520-00-237-5261. Manufacturer of record part number: 6X4BTR.

Also searched as 4520-00-237-5261 · 4520002375261 · NIIN 002375261 · 00-237-5261 · FSC 4520 Space and Water Heating Equipment · CAGE 34557 · 6X4BTR

Nearby stock numbers ← 4520-00-237-5260 · 4520-00-238-2437 →

Features

Reducer,flue Pipe — FSC 4520
1 manufacturer part number on file
Manufacturer of record: Masco Corp American Metal Products Co Div

Identification

NSN: 4520-00-237-5261
NIIN: 002375261
FSC: 4520 — Space and Water Heating Equipment
FSG: 45 — Plumbing, Heating, and Waste Disposal
Primary part number: 6X4BTR
Manufacturer: Masco Corp American Metal Products Co Div

General Description

The Reducer,flue Pipe, cataloged under National Stock Number 4520-00-237-5261, is classified within Federal Supply Class 4520 (Space and Water Heating Equipment) of the Plumbing, Heating, and Waste Disposal group. The manufacturer of record is Masco Corp American Metal Products Co Div. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. Current acquisition status: Active.

Catalog Facts

Item Name	Reducer,flue Pipe
FSC / FSG	4520 — Space and Water Heating Equipment (FSG 45)
Manufacturers	Masco Corp American Metal Products Co Div (CAGE 34557)

Technical Specifications

Parameter	Value
NSN	4520-00-237-5261
Primary Part Number	6X4BTR
Item Name	Reducer,flue Pipe
FSC / FSG	4520 / 45 — Space and Water Heating Equipment
Manufacturer	Masco Corp American Metal Products Co Div
Status	ACTIVE

Lifecycle & Compliance

Acquisition Status	ACTIVE
DEMIL Code	DEMIL A — No Demilitarization Required
Hazard	No hazard code in the DLA record (HMIC N)

Cross-Reference Index

Part Number	Manufacturer
6X4BTR PRIMARY	Masco Corp American Metal Products Co Div (USA)

No interchangeability data on file.

Other items in FSC 4520 — Space and Water Heating Equipment

Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.

4520-00-000-0098

HEATING ELEMENT,ELECTRICAL,NONIM

4520-00-000-0099

4520-00-000-0099 · Item name not on file

4520-00-001-1240

4520-00-001-1240 · Item name not on file

4520-00-001-3518

HEATING ELEMENT,ELECTRICAL,NONIM

4520-00-001-3519

HEATING ELEMENT,ELECTRICAL,IMMER

4520-00-001-6052

HEATING ELEMENT,ELECTRICAL,NONIM

4520-00-001-6298

HEATING ELEMENT,ELECTRICAL,NONIM

4520-00-001-7726

HEATER,DUCT TYPE,PORTABLE

Frequently Asked Questions

What is NSN 4520-00-237-5261?

NSN 4520-00-237-5261 is a Reducer,flue Pipe, manufactured by Masco Corp American Metal Products Co Div, classified under FSC 4520, Space and Water Heating Equipment. Status: active.

What part numbers are listed for NSN 4520-00-237-5261?

NSN 4520-00-237-5261 has 1 manufacturer part number on file: 6X4BTR (Masco Corp American Metal Products Co Div).

Is NSN 4520-00-237-5261 hazardous material?

No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.

Sources

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.

✓ Data cited from the U.S. Government catalog; commercial cross-references from OEM and certified industry sources.

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