LOMO Microscope Objective - Achromat 18x0.30

Can't find this objective in my reference books. It is for a metallographic microscope, most probably.

Magnification: 18x
Numeric aperture: 0.30
Iris diaphragm: No
Immersion: None
Parfocal height: 33mm (RMS) ?
Correction : Achromat
Spectrum range: 400-700nm
Research method: None
Contrast method: None