ECSiNG 20PCS PD Ruler Pupil Distance Measuring Ruler Digital Callipers 17.7x2.2mm for Eyeglasses Pupil Measurement Tool for Hospitals Pharmaceutical or Medical Items
[Durable PVC Material] Made of PVC for long-lasting durability.
[Compact Size] Dimensions: 17.7x2.2mm, easy to handle and store.
[Easy to Use] Simply place the notch of the PD ruler on the nose, align with the eyes, and read the nearest line corresponding to the center of the pupils.
[Versatile Application] Ideal for optometry procedures, measuring the distance between the eyes and the height from the pupils to the bottom of the lens.
[Bulk Quantity] Includes 20 pieces of pupillary distance measurement rulers for ample supply.