Tefillin are two small black boxes with black leather straps attached to them; Jewish men are required to place one box on their head and tie the other one on their arm each weekday morning.
Putting on Tefillin is one of the most important Mitzvot in the Torah. Bat Mitzvah boys and men celebrating their Bar Mitzvah, usually receive a new Pair of Tefillin.
Tefillin is also called Phylacteries from the Greek meaning "to Guard".
Tefillin - Kosher with Covers