“d” shaped object, diam. 50mm : POD069150

The “d” shape does not present symmetry axis. Therefore, it is adapted for observing all image inversions.
As the “d” size is known, this shape enables the widening measurements.
The shape object is made of black metal token.

Ø 50 mm is adapted to the light source, Ref. POD 069 120.

Diam. 50 mm