This is a beautiful hand made mezuzah from the house of artist Chen.
The choshen is the 12 stones that Aharon the brother of Moses had on him to symbolize the 12 tribes of Israel.
* The sizes of the mezuzahs are:
AL/101 - 5.6"
AL/102 - 6.4"
AL/103 - 6.4"
AL/104 - 7"