Apparatus for calibration of GAT, designed and validated by a GOC registered optometrist. Features stainless steel calibration weights 1g, 2g and 5g (accurate to +\- 0.005g) and a set of 4 weight holders (engraved 0, 1, 2 or 5, respectively). Full instructions included, though it is intuitive (more so than the original rod). The calibration described is 4-point (0, 1, 2, 5g) whereas the original method is 3-point (0, 2, 6g). What you will receive is shown in the second photo, though you will also receive a plastic custom made case. There is a prism included only for use in the calibration procedure of GAT or Perkins (it is a dimensional and weight replica); it has no other known uses.
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