Jackson Cross Cylinder 0.25

Hiding Heidi Low Contrast Face Test are available in 2 different versions:

Double Sided : Four cards printed on both sides in the following Contrast levels: black, 25%, 10%, 5%, 2.5%, and 1.25%.

Single Sided : Seven cards printed on one side in the following Contrast levels: black, 25%, 10%, 5%, 2.5%, and 1.25%.

Cards are 9″ x 9″ (23 cm x 23 cm). Includes instructions.