PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

S221Test Set,automatic Smoke Alarm

Regin Hvac Products, Inc. · NSN 6635-01-678-5945 · FSC 6635 · No Item Name Available
Verified by PartsTable
NSN 6635-01-678-5945 — this item is cataloged by the U.S. Government under National Stock Number 6635-01-678-5945. Primary manufacturer part number: S221.
Features
  • Test Set,automatic Smoke Alarm — FSC 6635
  • 2 verified cross-references
  • Primary manufacturer: Regin Hvac Products, Inc.
Applications
  • Industrial maintenance and repair
  • Government and military logistics
  • Equipment overhaul and refurbishment
General Description

The Test Set,automatic Smoke Alarm, cataloged under National Stock Number 6635-01-678-5945, is classified within Federal Supply Class 6635 (No Item Name Available) of the Instruments and Laboratory Equipment group. The primary manufacturer of record is Regin Hvac Products, Inc.. This item has 2 commercial cross-references from 2 manufacturers, enabling identification through both NSN and commercial part number lookups. 10 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN6635-01-678-5945
Primary Part NumberS221
Item NameTest Set,automatic Smoke Alarm
FSC / FSG6635 / 66 — No Item Name Available
ManufacturerRegin Hvac Products, Inc.
StatusACTIVE
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 10
5120-00-042-7848S22-1 INTERCHANGEABLE
Die,crimping Tool
Souriau Usa, Inc. Dba Souriau Usa Inc
4720-00-059-5819S50HL1-4X3-8X50 INTERCHANGEABLE
Tubing,nonmetallic
Saint-Gobain Performance Plastics
9540-00-147-7721 INTERCHANGEABLE
Channel,structural
4720-00-555-2896R210-1 1/2X5/8 9FT INTERCHANGEABLE
Tubing,nonmetallic
Mayon Plastics Inc
6625-00-765-5690 INTERCHANGEABLE
Network,test Set
5930-00-823-7305101904MY INTERCHANGEABLE
Switch,rotary
Electro Switch Corp. Dba Electro Switch Corp
4820-01-143-4307 INTERCHANGEABLE
Valve,gate
5310-01-229-7791S-221 INTERCHANGEABLE
Nut
Cummins Inc.
5120-01-616-2598S221 INTERCHANGEABLE
Pliers
Swanstrom Corp Swanstrom Tools Usa Div
5120-01-661-7184S221 INTERCHANGEABLE
Socket,socket Wrench
Idsc Holdings Llc Div Snap-on Industrial, a Div. of Idsc Holdings , Llc
Cross-Reference Index
Part NumberManufacturer
4101T7 Mcmaster-Carr Supply Co (USA)
S221 PRIMARY Regin Hvac Products, Inc. (USA)
Related Parts
5120-00-042-7848INTERCHANGEABLE
DIE,CRIMPING TOOL
S22-1
4720-00-059-5819INTERCHANGEABLE
TUBING,NONMETALLIC
S50HL1-4X3-8X50
9540-00-147-7721INTERCHANGEABLE
CHANNEL,STRUCTURAL
4720-00-555-2896INTERCHANGEABLE
TUBING,NONMETALLIC
R210-1 1/2X5/8 9FT
6625-00-765-5690INTERCHANGEABLE
NETWORK,TEST SET
5930-00-823-7305INTERCHANGEABLE
SWITCH,ROTARY
101904MY
4820-01-143-4307INTERCHANGEABLE
VALVE,GATE
5310-01-229-7791INTERCHANGEABLE
NUT
S-221
5120-01-616-2598INTERCHANGEABLE
PLIERS
S221
5120-01-661-7184INTERCHANGEABLE
SOCKET,SOCKET WRENCH
S221

Frequently Asked Questions

What is NSN 6635-01-678-5945?

NSN 6635-01-678-5945 is a Test Set,automatic Smoke Alarm, manufactured by Regin Hvac Products, Inc., classified under FSC 6635 (No Item Name Available). Status: active.

What are the part numbers for NSN 6635-01-678-5945?

NSN 6635-01-678-5945 has 2 cross-referenced part numbers: 4101T7 (Mcmaster-Carr Supply Co), S221 (Regin Hvac Products, Inc.).

What NSN replaces 6635-01-678-5945?

There are 10 known substitutes for 6635-01-678-5945: 5120-00-042-7848, 4720-00-059-5819, 9540-00-147-7721 and 7 more. Verify interchangeability with system specifications before substitution.

What are the specifications of S221?

Key specifications for S221: Part Name Assigned by Controlling Agency: SMOKE STICK REFILL PACK; End Item Identification: REGIN SMOKE PEN; Special Features: PACKAGE OF 6 WICK FOR REGIN SMOKE PEN P/N : S220; COLOR: BEIGE; FLASH POINT: 165.00 DEG. C.; INSOLUBLE;. 3 total characteristics are documented in the Federal Logistics Information System.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
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