Linen Testers are strong magnifiers with a measuring scale. Historically
they were (and still are) used to check the thread size and the number of woven threads per square inch. They are also used extensive in the graphic designing, desktop publishing, film and plate, photo negatives and agriculture.
The purpose of using a Linen Tester is to inspect quality, check fine measurements
and colour separations in graphics, measure small details and view of postage
stamps, coins, examine prints or negatives.
High quality, 6X magnification, double lenses to reduce aberration
and distortion, 25 mm scale plate in metric and imperial measurements.