The Mezuzah is an ornamental item placed on the doorpost of a Jewish home or institution. It contains the text of Deuteronomy, “Shema Israel, Adonia Eloheinu, Adonia Echad” (Hear O Israel! The Lord our God, the Lord is one!).
The Hebrew letter 'sh' is usually seen on the outside of a mezuzah representing the 'Sh' in Shema (hear). The Mezuzah comes in many shapes and sizes.