D83mm MOUNT OUTER DIAMETER INDUSTRIAL near 200mm FOCAL PLANE.
CONVEX-PLANO HQ COATED, WELL-CORRECTED GLASS.
LITTLE COATING MARKS on IT- NOT AFFECTED USE.
BARREL D82.5mm x 35mm. GLASS D74.5mm.
OPTICALLY WELL CORRECTED.

IT MAY BE COUPLED WITH OTHER HQ MAGNIFIERS / PEAK LIKE/, I THINK.