The Comparator – PW Tam 135273 is a transparent plastic device with highly fluorescent markings, which is used in the inspection booth to assess the size of defects, both linear and round. This Tam Comparator provides markings for linear and round indications in inches with metric equivalent. These indications range from .180 (4.6mm) to .010 (0.2mm). Meets Pratt & Whitney Specifications.