I beleive I have a couple of plates as listed below not sure if there is any value to these plates and what condition issue mine may have I have three plates total and they measure different sizes from 19 3/4" x 19 3/4" with 60 lines per inch down to 12" x 12" 70 lines per inch. One plate has a couple of scratches while another plate has some discoloration on the edge all have a metal banding. Should I list these items at all or are they garbage? Look below for full description.

These precision English and Metric Grid and Dot Arrays are manufactured from Select Soda Lime Glass and are furnished with a Certificate of Accuracy with N.I.S.T Traceability. They are ideally suited for set up and calibration of Optical and other Two Dimensional X-Y Stages and Measurement Systems. When built into our Air Cooled Light Boxes and used in conjunction with our MicroRules or MicroScales they provide a complete solution for measurement of photoplotted images, phototooling and two dimensional parts and features. They can also be built into OEM pattern generation and measurement equipment and used with Optical and X-Ray Machine Vision Systems for “on-the-fly” X-Y location and calibration.

Grid and Dot Patterns can be chrome on clear glass, low reflection chrome on clear glass, or etched into the clear glass and filled with MIL-I-43553 black (standard), white or red Epoxy. Composite Grid and Dot patterns, with high contrast low reflection black chrome against a diffuse white background, are provided for Machine Vision Applications using top “Thru-the Lens” and “Ring” lighting. Special high density “Doughnut” Dot Arrays are available for X-Ray Imaging and Inspection Systems. Proprietary etched Grid Patterns transparent to top and bottom lighting but visible with edge lighting and fluorescent patterns for deep UV applications are also available through our Sales Engineering Department.

Grid and Dot Arrays are available with and without protective edge frames. When edge frames are selected precision plastic glass support disks are provided to maintain the glass flatness for use of the pattern as a calibration source. A carrying case is also provided to protect the Grid or Dot Array during storage.

In addition to the standard “Certificate of Accuracy” with NIST Traceability, any Grid or Dot Array can be individually calibrated to provide “Certified Calibration” Traceable to N.I.S.T.