10pcs PD Ruler Eye Tool Plastic Practical for Hospital Clinic (White)

Made from premium material for long time use.
Lightweight for easy and portable carry. The optical PD ruler is soft and flexible,so it will not easily to break.
Put the notch over your nose, as close to your eyes as you can, then find the middle if your pupils in a mirror, read the line closest to the middle of the pupils.
It is a very good promotional item and for hospital, pharmaceutical or medical supplies.
If you dont know how to take a PD measurement, you will need to look that up on the internet.