Reticle 21mm Straight Line Rules 0-15mm and 0-.60 Inch This English and Metric Micrometer Scale Reticle is used for critical measurements of object features. The English Scale length is .60” with .010” increments; and, the Metric Scale length is 15mm with 0.1mm increments and Numerical markings every 1.0mm. The Scale line widths are .001”±.0001” (.025mm±.0025mm).The Pattern is right reading looking through the glass so that the pattern can be in direct contact with the object to be measured.The Reticle Pattern is very durable, double layer, deposited evaporative Chrome/Chrome Oxide, for a reflectivity of less than 5% looking at the pattern. The Patterns on all Reticles manufactured by Max Levy are replicated from Precision Chrome on Glass Tooling under clean room conditions. Click here to download drawing 21mm Compatibility Chart Full Compatibility Chart