Paterson micro grain focus finder for enlarging photographic Paper Prints[BDL]
The Paterson Focus Finder is an inexpensive but reliable laboratory instrument.
The 8 x magnification is more than enough for sharp focus.
You cannot see the grain as well as with 20 x magnification, but the image is bright and clear and you can see where you are in the picture.
The focus finder also has a diopter compensation adjustment for individual eyesight. #
There is a shutter to protect the mirror when not in use and a rubber cap to protect the lens.