A scale printed or designed on metal, transparent or opaque plastic, cardboard or other material to measure the number of perforation holes or teeth within the space of 2 centimeters.

Used to measure the perforations used to separate stamps. Consists of a simple printed or engraved card made of paper, metal, or plastic which is imprinted with various perforations, generally in whole and half measures, which can be compared with the stamp in question. Measurements of perforations less than 1/2 perforation are often unreliable because of paper shrinkage which occurs when stamps are dampened for printing or soaked to remove them from the envelope.