Prefix Key: "18" 1800 series intensifiers. "20" 2000 series intensifiers. "22" 2200 series intensifiers. "24" 2400 series intensifiers.
Suffix Key: "U" Unlimited FOM not capped for export. "M" Military Spot Specification. "A" Aviator Spot Specification. Additionally, there may be another suffix qualifier added after the spot specification. This is known as a "smart number" for special order requests. Also known as OID.
This is where the tube designations derive from: 18UM, 20UA, 22UM, etc.
L3Harris 1800 Series (18UM) Unfilmed White Phosphor:
- SNR: 24.1 minimum
- FOM: 1540 minimum
- Center Resolution: 64 minimum
L3Harris 2000 Series (20UM/UA) Unfilmed White Phosphor:
- SNR: 28 minimum
- FOM: 1792 minimum
- Center Resolution: 64 minimum
- Halo: 1.0 maximum
L3Harris 2200 Series (22UM/UA) Unfilmed White Phosphor:
- SNR: 30 minimum
- FOM: 1920 minimum
- Center Resolution: 64 minimum
- Halo: 1.0 maximum
L3Harris Unfilmed White Phosphor 1610 tubes. Applicable to PVS-31A and BNVD-1531 (2376+ FOM models):
- SNR: 33 minimum
- FOM: 2376 minimum
- Center Resolution: 72 minimum
- Halo: 0.85 maximum
*in some instances L3Harris will elect to omit certain thresholds in qualifying tube performance, sometimes in favor of FOM value over minimum SNR or resolution values.
Image Quality Performance Specification:
A spot must be larger than .003 inches to qualify as a dark spot. Under this size is referred to as peppering and is allowed in any zone in any quantity.
Military/Ground Spot Specification:
| Spot Size | Zone 1 | Zone 2 | Zone 3 |
| (Inches) | Limit | Limit | Limit |
| >.012 | 0 | 0 | 0 |
| >.009 | 0 | 0 | 0 |
| >.006-.009 | 0 | 1 | 1 |
| >.003-.006 | 0 | 2 | 2 |
| Bright Spots | 0 | 0 | 0 |
| Dark spots </= .003” are acceptable |
Aviator Spot Specification:
| Spot Size | Zone 1 | Zone 2 | Zone 3 |
| (Inches) | Limit | Limit | Limit |
| >.012 | 0 | 0 | 0 |
| >.009 | 0 | 0 | 0 |
| >.006-.009 | 0 | 0 | 1 |
| >.003-.006 | 0 | 0 | 2 |
| Bright Spots | 0 | 0 | 0 |
|
Dark spots </= .003” are acceptable |