There are two optics with this instrument: one low magnification and one high-magnification objective. They may be ganged together for higher magnification. Each is a simple bi-convex lens.
The mirror has one parabolic reflecting surface. It is fastened to the pillar buy pressing the peg through a hole. Dia=2.2cm
The two objectives are simple biconvex lenses. A: dia=7mm, f=10mm; B: dia=11mm, f=25mm