Plastics in Optics PD Rule and Contact Lens Diameter Gauge

Description Of Item: White plastic rule 158 mm x 28 mm x 2 mm with bevelled edges on face printed in black with a centimetre scale with millimetre divisions on the upper edge and an inch scale with sixteenths divisions on lower edge. Central section is imprinted 'Plastics in Optics Subsidiary of Barnes-Hind International' and a Barnes-Hind logo. The reverse is a diameter gauge for rigid corneal contact lenses using a tapered groove to measure diameters from 6 mm to 11.5 mm. A scale is printed in black has 0.1 mm divisions above the groove and the words 'LENS DIA GAGE' are printed below.