ALargeItemThresholdUnits

Optional. This setting is equivalent to the units entry for Never Archive Items Younger Than on the Archiving Rules tab of the Exchange Mailbox Policy dialog box.

This setting is for the filters that are associated with the mailbox, and it does not apply to other folders.

If you specify ALargeItemThresholdUnits, you must also set values for all the following:

UseInactivityPeriod (must be set to true)
APrioritizeLargeItems
APrioritizeItemsOver
ALargeItemThresholdPeriod

Possible values:

Days
Weeks
Months
Years