Usage: This product is suitable for optical shop, hospital ophthalmology, schools, factories and mining enterprises for visual inspection. Features: monocular movement range 25mm-40mm; PD, eye height, ear height can be adjusted. 1. pupil distance adjustment range: binocular pupil distance 48 - 80mm, left or right pupil distance 24 - 40mm, scale value 1mm. 2. indexing disc axis: left indexing disc 120°- 0°-135°; Right indexing plate 45°-180°-60° The axis scale increases counterclockwise along the axis of the frame, and the marking interval is 5°. 3. The aperture inside the frame:32.5mm. 4. Left or right frame can be inserted at the same time the number of lenses: 4 pieces. 5. The lens in the frame around the optical axis rotation degree: 360° 6. The optical axis of the lens and the geometric axis of the frame is not parallel: less than equal 2.5° 7. Lens optics and frame geometry of the different heart: less than equal 0.5mm. 8. The displacement of the lens relative to the geometric position of the frame: less than equal 0.3mm. 9. Nasal support adjustment range: length: 0-14mm; Angle: 0°-30°. 10. Left or right mirror foot length adjustment range: 98mm-135mm. 11. Left and right mirror foot spacing: 200mm. Colour:As Shown Material:Aluminum Alloy Package Contents: 1 x Universal Trial Lens Frame Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.