| ELEMENT LEFT SURFACE RADIUS | 5.3640 INCHES |
| ELEMENT RIGHT SURFACE RADIUS | 1.0420 INCHES |
| ABBE CONSTANT | 33.800 AND 58.800 |
| AXIAL THICKNESS | 0.121 INCHES NOMINAL AND 0.210 INCHES NOMINAL |
| COMPOUND LENS EDGE THICKNESS | 0.306 INCHES NOMINAL |
| COMPOUND LENS OVERALL AXIAL THICKNESS | 0.331 INCHES NOMINAL |
| COMPOUND LENS STYLE | DOUBLET |
| DIAMETER | 0.984 INCHES NOMINAL |
| EQUIVALENT FOCAL LENGTH | 4.739 INCHES |
| FRONT FOCAL LENGTH | 4.628 INCHES |
| FSC APPLICATION DATA | SIGHT PERISCOPE M28,INTEGRATED WITH FIRE CONTROL EQUIPMENT |
| INDIVIDUAL LENS STYLE | DOUBLE CONVEX |
| MATERIAL DOCUMENT AND CLASSIFICATION | MIL-G-174, CLASS 1, GRADE C MIL SPEC SINGLE MATERIAL RESPONSE |
| MATERIAL | GLASS OPTICAL |
| REFRACTION INDEX | 1.6110 MINIMUM AND 1.6490 MAXIMUM |