PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

1040155Window,optical Instrument

Navair and Navsea Managed Original Design Activity Dwg Not Material/parts Supplier · NSN 1240-00-171-4178 · FSC 1240 · No Item Name Available
Verified by PartsTable
NSN 1240-00-171-4178 — this item is cataloged by the U.S. Government under National Stock Number 1240-00-171-4178. Primary manufacturer part number: 1040155.
Features
  • Window,optical Instrument — FSC 1240
  • Polished Periphery: NOT PROVIDED
  • Refraction Index: 1.5170 NOMINAL
  • Thickness: 5.800 MILLIMETERS MINIMUM AND 6.200 MILLIMETERS MAXIMUM MM
  • Diameter: 50.950 MILLIMETERS MINIMUM AND 51.000 MILLIMETERS MAXIMUM MM
  • Material: GLASS OPTICAL LOCATION NOT OTHERWISE SPECIFIED
  • Material Document and Classification: JAN-G-174, TYPE 517-645, GRADE B MIL SPEC SINGLE MATERIAL RESPONSE LOCATION NOT OTHERWISE SPECIFIED
  • FSC Application Data: TELESCOPE MK 102 MOD 3
Applications
  • Applications requiring Glass Optical Location Not Otherwise Specified construction
General Description

The Window,optical Instrument, cataloged under National Stock Number 1240-00-171-4178, is classified within Federal Supply Class 1240 (No Item Name Available) of the Fire Control Equipment group. The primary manufacturer of record is Navair and Navsea Managed Original Design Activity Dwg Not Material/parts Supplier. Government technical data includes 12 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 2 commercial cross-references from 2 manufacturers, enabling identification through both NSN and commercial part number lookups. 3 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN1240-00-171-4178
Primary Part Number1040155
Item NameWindow,optical Instrument
FSC / FSG1240 / 12 — No Item Name Available
ManufacturerNavair and Navsea Managed Original Design Activity Dwg Not Material/parts Supplier
StatusACTIVE
Polished PeripheryNOT PROVIDED
Refraction Index1.5170 NOMINAL
Thickness5.800 MILLIMETERS MINIMUM AND 6.200 MILLIMETERS MAXIMUM MM
Diameter50.950 MILLIMETERS MINIMUM AND 51.000 MILLIMETERS MAXIMUM MM
MaterialGLASS OPTICAL LOCATION NOT OTHERWISE SPECIFIED
Material Document and ClassificationJAN-G-174, TYPE 517-645, GRADE B MIL SPEC SINGLE MATERIAL RESPONSE LOCATION NOT OTHERWISE SPECIFIED
FSC Application DataTELESCOPE MK 102 MOD 3
Polished SurfaceBOTH
Bevel Depth0.750 MILLIMETERS NOMINAL MM
Reflection Reducing SurfaceBOTH
Bevel Angle in Deg45.000 NOMINAL
Dispersion64.5 ANGSTROMS NOMINAL
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 3
1610-00-127-651752476 INTERCHANGEABLE
Lug,stop
Hamilton Sundstrand Corporation Dba Collins Aerospace
5340-01-434-2219 INTERCHANGEABLE
Bracket,mounting
4730-01-503-7906104-155 INTERCHANGEABLE
Adapter,straight,pipe to Tube
Crane Carrier Company, Llc
Cross-Reference Index
Part NumberManufacturer
1040155 PRIMARY Navair and Navsea Managed Original Design Activity Dwg Not Material/parts Supplier (USA)
52476 Optical Technology Devices Inc (USA)
Related Parts
1610-00-127-6517INTERCHANGEABLE
LUG,STOP
52476
5340-01-434-2219INTERCHANGEABLE
BRACKET,MOUNTING
4730-01-503-7906INTERCHANGEABLE
ADAPTER,STRAIGHT,PIPE TO TUBE
104-155

Frequently Asked Questions

What is NSN 1240-00-171-4178?

NSN 1240-00-171-4178 is a Window,optical Instrument, manufactured by Navair and Navsea Managed Original Design Activity Dwg Not Material/parts Supplier, classified under FSC 1240 (No Item Name Available). Status: active.

What are the part numbers for NSN 1240-00-171-4178?

NSN 1240-00-171-4178 has 2 cross-referenced part numbers: 1040155 (Navair and Navsea Managed Original Design Activity Dwg Not Material/parts Supplier), 52476 (Optical Technology Devices Inc).

What NSN replaces 1240-00-171-4178?

There are 3 known substitutes for 1240-00-171-4178: 1610-00-127-6517, 5340-01-434-2219, 4730-01-503-7906. Verify interchangeability with system specifications before substitution.

What are the specifications of 1040155?

Key specifications for 1040155: Polished Periphery: NOT PROVIDED; Refraction Index: 1.5170 NOMINAL; Thickness: 5.800 MILLIMETERS MINIMUM AND 6.200 MILLIMETERS MAXIMUM MM; Diameter: 50.950 MILLIMETERS MINIMUM AND 51.000 MILLIMETERS MAXIMUM MM. 12 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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