Although "tefillin" is technically the plural form (the singular being "tefillah"), it is often used as a singular as well. The arm-tefillah (or shel yad [literally "of the hand"]) is placed on the upper (non-dominant) arm, and the strap wrapped around the forelimb, hand and middle finger; while the head-tefillah (or shel rosh [literally "of the head"]) is placed between the eyes at the boundary of the forehead and hair. They are intended to fulfill the Torah's instructions to maintain a continuous "sign" and "remembrance" of the Exodus from Egypt. While historically men used to wear tefillin all day, this is no longer common. The general practice today is to remove them following services.
Although "tefillin" is technically the plural form (the singular being "tefillah") it is often used as a singular as well The arm-tefillah (or shel yad [literally "of the hand"]) is placed on the upper (non-dominant) arm and the strap wrapped around the forelimb hand and middle finger; while the head-tefillah (or shel rosh [literally "of the head"]) is placed between the eyes at the boundary of the forehead and hair They are intended to fulfill the Torah's instructions to maintain a continuous "sign" and "remembrance" of the Exodus from Egypt While historically men used to wear tefillin all day this is no longer common The general practice today is to remove them following services