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1.Pupil distance range: 52；54; 56; 58; 60mm.
2.Axis scale: left scale: 0°~180°~60°; right scale: 180°~0°~120°. The axis scale increases anticlockwise along the axis of the frame, and the marking interval is 5°.
3.Effective internal aperture of frame: 38mm.
4.The number of lenses that can be inserted into the left and right frames: 4 (the front is 3 and the rear is 1).
5.Rotation degree of optical axis of lens in inner ring of frame: 360 °.
6.The nonparallelism between the optical axis of the lens and the geometric axis of the frame: ≤2.5 °.
7.The difference between the optical center and the geometric center of the lens: ≤0.5mm.
8.Displacement of the lens relative to the geometric center of the frame: ≤0.3mm.
9.Adjustable length range of the left and right frame leg: 125~155mm. (Eight trial frames are in one group.Trial frames in different colors have different pupil distance) Clinical application: Combined with optometry lens for refractive examination of human eyes.