PVS-31A, 2376+ FOM

SPEC KEY:

Hand-Select Night Vision includes actual specs of the tube(s) included in your night vision device as listed on the tube manufacturer's data sheet. The data sheet serves as a certificate of conformance to demonstrate that tubes meet or exceed their quality and performance standards.

For a breakdown of L3Harris' various tube options and associated minimum performance, please see our guide to Minimum Specifications and Spots. Guides discussing specs are available under the "Resources" tab

FOM = Figure of Merit

SNR = Signal to Noise (Numeric)

RES (or CR) = Center Resolution (line pairs / mm)

HALO = Halo (mm)

EBI = Equivalent Background Illumination

Provided images through the tubes are captured on a Hoffman Engineering 126A. The digital imaging process can cause slight color and brightness variations between images. White phosphor tubes appear white to the eye. Images may may not depict all cosmetic details in every lighting evironment. Every night vision device has some degree of peppering or small spots at or below .003" (the smallest countable size depicted on a data sheet).

Q: Why do some pictures look more blue vs. green? Is one better? Also, some appear to be brighter than others. 

A: Color differences are primarily caused by taking digital images of tubes and are not reflective of tube performance. Tube pictures are provided to show spots and cosmetic blemishes.  White phosphor tubes will appear white to the eye - not blue or green, though there can be very slight variation among tubes.

Q: Why do some tubes contain dark spots?

A: Spots are caused by the manufacturing process of night vision intensifier tubes. Spots aren't an indication of performance and exist in nearly every tube (though some tubes may exhibit larger spots than others). Military Spot spec tubes permit countable spots (those larger than .003") in zone 2 and zone 3 (the rings outside of the bullseye on a dart board), whereas aviation spot spec tubes only permit countable spots in zone 3 (outer periphery of the tube, furthest from center).

 L3Harris | Minimum Specifications and Spots

Spots

L3Harris Tubes ending with UM or UA (ex. 18UM vs. 24UA) have differing tolerances for dark spots.

• UM (military) tubes permit spots greater than .003" (diameter) in Zone 2 and 3. Spots greater than .003" are not permitted in Zone 1.

• UA (aviation) tubes limit spots greater than .003" to Zone 3 only. This is L3's strictest spot spec.

• Dark spots less than or equal to .003" don't meet the threshold as a countable spot and are commonly referred to as "peppering".  

To reference the Zone regions, you can refer to the image above which shows a tube photographed on a Hoffman Engineering 126A test set. 

Military Spot Spec:

Despite adding up to 6 total (above), L3 tubes are limited to 4 spots max

Aviation Spot Spec: 

Performance

L3Harris unfilmed tubes are available with various minimum performance levels (18, 20, 22, 24).

The higher the performance series number (i.e. 20 vs. 18), the higher the minimum performance.

This performance series is then combined with a spot spec to identify the tube. For example, the 18 performance series, with unlimited FOM ("U"), and Military ("M") spot spec would be 18UM. 

Tube Model Performance summary:

• Center Resolution: 64 lp/mm minimum
• FOM: 1540 minimum
• Halo: 1.0 maximum
• EBI: 2.5 maximum

• Center Resolution: 64 lp/mm minimum
• FOM: 1792 minimum
• Halo: 1.0 maximum
• EBI: 2.5 maximum

• Center Resolution: 64 lp/mm minimum
• FOM: 1920 minimum
• Halo: 1.0 maximum
• EBI: 2.5 maximum

• Center Resolution: 64 lp/mm minimum
• FOM: 2160 minimum
• Halo: 1.0 maximum
• EBI: 2.5 maximum

• SNR: 36 minimum
• Center Resolution: 64 lp/mm minimum
• FOM: 2304 minimum (implied)
• Halo: 1.0 maximum
• EBI: 2.5 maximum
• Aviation Spot Spec (Spots limited to Zone 3 only)

Other:

• SNR: 33 minimum
• FOM: 2376 minimum
• Center Resolution: 72 lp/mm minimum
• Halo: 0.85 maximum
• EBI: 2.5 maximum
• Military Spot Spec (Spots permitted in Zone 2 and Zone 3)

Please be advised: night vision, thermal, and certain accessories you purchase from Apollo Gear LLC are controlled technologies.

As such, by purchasing products from Apollo Gear LLC, you acknowledge and agree to the following statements:

• These products and technologies are subject to one or more of the export control laws and regulations of the U.S. Government and may fall under the control jurisdiction of either the Department of State’s International Traffic in Arms Regulations (ITAR) or the Department of Commerce’s Export Administration Regulations (EAR).

• It is unlawful to export, or attempt to export or otherwise transfer or sell any hardware or technical data or furnish any service to any foreign person, whether abroad or in the United States (U.S.), for which a license or written approval of the U.S. Government is required, without first obtaining the required license or written approval from the department of the U.S. Government having jurisdiction.

• I understand that, in the ITAR (§ 120.16), a foreign person means any natural person who is not a lawful permanent resident as defined by 8 U.S.C. 1101(a)(20) or who is not a protected individual as defined by 8 U.S.C. 1324b(a)(3). It also means any foreign corporation, business association, partnership, trust, society or any other entity or group that is not incorporated or organized to do business in the U.S., as well as international organizations, foreign governments and any agency or subdivision of foreign governments (e.g., diplomatic missions).

• I understand that I am responsible for compliance with any and all U.S. Government export controls and regulations and that, if I violate them, it could result in severe criminal and civil penalties (including substantial fines, imprisonment, seizure of controlled products and technical data, among other penalties, for me and/or any company I represent).

• I understand I am purchasing this equipment for use in the United States only.

• I understand and agree that these items will not be exported, provided to foreign persons in the U.S. (including Foreign Embassies in the U.S.) or sold domestically for export by a third party (including U.S. Government agencies).

• I understand if these items are sold, it is my responsibility to advise the purchaser of their duty to comply with U.S. export control regulations or face the possibility of severe criminal and civil fines, including imprisonment.

• I understand it is my obligation to obtain and retain a record of the sale if these items are sold.

• I will inform Apollo Gear LLC if these products are lost, stolen or destroyed, and provide the date of the incident as well as the associated serial number of the item so that Apollo Gear LLC can maintain information for its records and may provide it to the proper regulating authority.

By purchasing any product from Apollo Gear LLC, you agree that you will abide by our Terms of Service.