An essential item for dispensing opticians, the ABDO frame rules was designed by George Clayton and is produced by the Association of British Dispensing Opticians.

The rule will enable the user to accurately measure the following:

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• Interpupillary Distance (PD)

• Boxed Lens Size (Horizontal and Vertical)

• Distance Between Lenses

• Boxed Centre Distance

• Crest Height

• Bridge Projection

• Distance Between Rims

• Bridge Height

• Bridge Width

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The white plastic rule which is 155mm x 60mm, measures 11 different frame dimensions and comes complete with a full instruction manual.