Ktav Stam (Hebrew: כתב סת״ם‎‎) is the specific Jewish traditional writing with which Torah scrolls (Sifrei Torah), phylacteries (Tefillin), Mezuzot and the Five Megillot are written. Stam is an acronym denoting these writings, as indicated by the gershayim (״) punctuation mark. One who writes such articles is called a Sofer Stam. The writing is done by means of a feather, and ink (known as D'yo) onto special parchment called klaf. There exist two primary traditions in respect to the formation of the letters, Ktav HaAshkenazi and Ktav HaSefardi, however the differences between them are slight.