Ophthalmic Trial Frame Optometry Refraction Glasses for Optical Shops PD size 48-80mm Axial scale of the dividing disk 130 °~ 0 °~ 120 °on the left and 50 °~ 180 °~ 60 °on the right. Effective internal aperture of mirror frame 33.5mm number of lens each side 5pcs the lens rotates around the optical axis in the inner circle of the lens frame 360 ° the lens optics The unparallelism between the axis and the geometric axis of the frame ≤ 2.5 ° the difference between the optical center and the geometric center of the lens ≤ 0.5mm he displacement of the lens relative to the geometric center of the frame ≤ 0.3 mm nose Range of adjustment: adjustable length 0 ≤ 22 mm; Angle: 360 ° adjustable length range of left or right foot 0~20mm weight 53g