1) The measurement range of the top focal is at least from -20D to +20D.
2) The measurement range of prism degree is at least from 0 to 5△.
3) The scale range of the column mirror axis should be from 00 to 1800, and the baseline direction of the prism between 00 and 3600 can be determined.
4) The size of the measurable lens should at least meet the requirements of measuring the diameter of 80mm and the thickness of 20mm lenses.