Feature: The pd ruler can help you when you want to buy glasses online. Put the notch over your nose, as close to your eyes as you can, then find the middle if your pupils in a mirror. Come With 8 different types rulers which suits different need. Straight edge with nose bridge design, well positioned and perfectly match on nose making the PD measurement easily and accurately. Double-side high-definition printing, for left-handed or right-handed use purpose, easy to measuring your PD at home. Description: Product name:PD Optometric Ruler Material:Plastics Size:About 18*2cm/7.09*0.79in Color: as picture shown Package Included: 1Pcs PD Optometric Ruler Note: 1. Due to the different monitor and light effect, the actual color of the item might be slightly different from the color which is showed on the pictures. 2. Please forgive 1 cm/0.39"-3 cm/1.18" measuring deviation due to manual measurement.