| ELEMENT LEFT SURFACE RADIUS | 6.614 INCHES |
| ELEMENT RIGHT SURFACE RADIUS | 2.728 INCHES |
| ABBE CONSTANT | 63.500 AND 43.600 |
| AXIAL THICKNESS | 0.450 INCHES NOMINAL AND 0.232 INCHES NOMINAL |
| BACK FOCAL LENGTH | 11.879 INCHES |
| COMPOUND LENS EDGE THICKNESS | 0.500 INCHES NOMINAL |
| COMPOUND LENS OVERALL AXIAL THICKNESS | 0.682 INCHES NOMINAL |
| COMPOUND LENS STYLE | DOUBLET |
| DIAMETER | 2.200 INCHES NOMINAL |
| EQUIVALENT FOCAL LENGTH | 12.237 INCHES |
| FSC APPLICATION DATA | PERISCOPE,M20A28 INTEGRATED WITH FIRE CONTROL EQUIPMENT |
| INDIVIDUAL LENS STYLE | DOUBLE CONVEX AND MENISCUS DIVERGING |
| MATERIAL DOCUMENT AND CLASSIFICATION | JAN-G-174, GRADE B MIL SPEC SINGLE MATERIAL RESPONSE |
| MATERIAL | GLASS OPTICAL |
| REFRACTION INDEX | 1.5110 NOMINAL AND 1.6053 NOMINAL |