Air Force resolution test targets are designed to numerically test optical system performance and provide calibration for microscope systems. These high-resolution USAF targets, which conform to the USAF-1951 resolution target standard, have a minimum line width as small as 137 nanometers, ideal for testing within the limits of super-resolution microscopes. The actual target pattern is located in the diamond-shaped aperture at the center of the target slide. The target slide contains six target group designations (group 6 thru group 11) making a total of 36 different targets. Within each group, there are 6 different line-pair targets. The first target in group 6 has a line width of 7.813µm and the 6th target in the 11th group has a line width of 0.137 µm.