This listing is: 3mm Uppercase Antlia Alphabet Letter Set consisting of Lowercase letters A-Z as well as exclamation Point and Ampersand. This measurement is based on the average size ascender/descender letters. Every letter is not 3mm. Our Sharper Lines and high rockwell hardness rating make it good for use on stainless steel blanks. Please accept our apologies, the laser engraving on the side of the shank was mismarked at 1.5 mm. The size of the stamp impression is correct.