Each letter set comes in ImpressArt's patented sleek storage case. The case features labeled slots for each stamp to keep them organized and for easy access. Size: 4mm** Uppercase includes full uppercase alphabet and 7 bonus design stamps Features: Tapered stamp heads, when needed, for precise placement Extra sharp character designs for crisp impressions Character marked on side of stamp for easy identification & orientation Rated for soft and hard metals up to Stainless Steel* Lightly coated with oil to prevent rust Storage case with labeled slots for each stamp *Rated for stamping on Alkemé, aluminum, pewter, copper, brass, silver, gold, Stainless Steel 304-308, & other metals up to 66HRC Rockwell Hardness. *Size is based off of the height of capital letters and the tallest lowercase letter.