For some curb items (or more generally, items measured in volume), often inspectors may want to measure the length of the item placed if the area of the placement along the measured length is known. If the area is known across the project, Project Managers and Admins can set that area on the item's settings in the Project > Items page by clicking the settings gear box icon on the particular item in the table.
Now, when an Inspector uses the Area x Measured length calculation in that project on that item, the area value will be prefilled with the setting value, saving them a step!
Note that the Area x Measure length calculation can be used even if the area is not set in the item's settings.